Перейдем в  папку, доступную для web сервера, например /var/www. Установим composer asset plugin, который позволяет управлять зависимостями пакетов bower и npm через composer. Эту команду достаточно выполнить один раз.

composer global require "fxp/composer-asset-plugin:^1.2.0"

Changed current directory to /root/.config/composer
./composer.json has been created
Loading composer repositories with package information
Updating dependencies (including require-dev)
Package operations: 1 install, 0 updates, 0 removals
  - Installing fxp/composer-asset-plugin (v1.3.0): Downloading (100%)         
Writing lock file
Generating autoload files

Устанавливаем последнюю стабильную версию Yii2 в директорию basic:

composer create-project --prefer-dist yiisoft/yii2-app-basic basic

Во время установки активно идет обмен данными с github.com, поэтому количество запросов может превысить лимит github api. В этом случае скрипт попросить ввести token, который можно будет получить, имея учетную запись github. Перед этим скрипт выведет ссылку, по которой можно сгенерировать токен.

Installing yiisoft/yii2-app-basic (2.0.11)
  - Installing yiisoft/yii2-app-basic (2.0.11): Downloading (100%)         
Created project in basic
Loading composer repositories with package information
Updating dependencies (including require-dev)
Reading bower.json of bower-asset/jquery (1.11.3)       
Could not fetch https://api.github.com/repos/jquery/jquery-dist/commits/1472290917f17af05e98007136096784f9051fab, please create a GitHub OAuth token to go over the API rate limit
Head to https://github.com/settings/tokens/new?scopes=repo&description=Composer+on+yii+2017-04-07+2040
to retrieve a token. It will be stored in "/root/.config/composer/auth.json" for future use by Composer.
Token (hidden): 
Token stored successfully.
Package operations: 59 installs, 0 updates, 0 removals 
 - Installing yiisoft/yii2-composer (2.0.5): Downloading (100%) 
 - Installing swiftmailer/swiftmailer (v5.4.6): Downloading (100%) 
 - Installing bower-asset/jquery (2.2.4): Downloading (100%) 
 - Installing bower-asset/yii2-pjax (v2.0.6): Downloading (100%) 
 - Installing bower-asset/punycode (v1.3.2): Downloading (100%) 
 - Installing cebe/markdown (1.1.1): Downloading (100%) 
 - Installing ezyang/htmlpurifier (v4.9.2): Downloading (100%) 
 - Installing bower-asset/jquery.inputmask (3.3.4): Downloading (100%) 
 - Installing yiisoft/yii2 (2.0.11.2): Downloading (100%) 
 - Installing yiisoft/yii2-swiftmailer (2.0.6): Downloading (100%) 
 - Installing bower-asset/bootstrap (v3.3.7): Downloading (100%) 
 - Installing yiisoft/yii2-bootstrap (2.0.6): Downloading (100%) 
 - Installing yiisoft/yii2-debug (2.0.9): Downloading (100%) 
 - Installing bower-asset/typeahead.js (v0.11.1): Downloading (100%) 
 - Installing phpspec/php-diff (v1.1.0): Downloading (100%) 
 - Installing yiisoft/yii2-gii (2.0.5): Downloading (100%) 
 - Installing fzaninotto/faker (v1.6.0): Downloading (100%) 
 - Installing yiisoft/yii2-faker (2.0.3): Downloading (100%) 
 - Installing psr/log (1.0.2): Downloading (100%) 
 - Installing symfony/debug (v3.2.7): Downloading (100%) 
 - Installing symfony/polyfill-mbstring (v1.3.0): Downloading (100%) 
 - Installing symfony/console (v3.2.7): Downloading (100%) 
 - Installing stecman/symfony-console-completion (0.7.0): Downloading (100%) 
 - Installing sebastian/diff (1.4.1): Downloading (100%) 
 - Installing sebastian/recursion-context (2.0.0): Downloading (100%) 
 - Installing sebastian/exporter (2.0.0): Downloading (100%) 
 - Installing sebastian/comparator (1.2.4): Downloading (100%) 
 - Installing behat/gherkin (v4.4.5): Downloading (100%) 
 - Installing symfony/dom-crawler (v3.2.7): Downloading (100%) 
 - Installing symfony/css-selector (v3.2.7): Downloading (100%) 
 - Installing symfony/browser-kit (v3.2.7): Downloading (100%) 
 - Installing symfony/yaml (v3.2.7): Downloading (100%) 
 - Installing symfony/event-dispatcher (v3.2.7): Downloading (100%) 
 - Installing symfony/finder (v3.2.7): Downloading (100%) 
 - Installing psr/http-message (1.0.1): Downloading (100%) 
 - Installing guzzlehttp/psr7 (1.4.2): Downloading (100%) 
 - Installing sebastian/version (2.0.1): Downloading (100%) 
 - Installing sebastian/environment (2.0.0): Downloading (100%) 
 - Installing sebastian/code-unit-reverse-lookup (1.0.1): Downloading (100%) 
 - Installing phpunit/php-token-stream (1.4.11): Downloading (100%) 
 - Installing phpunit/php-text-template (1.2.1): Downloading (100%) 
 - Installing phpunit/php-file-iterator (1.4.2): Downloading (100%) 
 - Installing phpunit/php-code-coverage (4.0.8): Downloading (100%) 
 - Installing sebastian/resource-operations (1.0.0): Downloading (100%) 
 - Installing sebastian/object-enumerator (2.0.1): Downloading (100%) 
 - Installing sebastian/global-state (1.1.1): Downloading (100%) 
 - Installing doctrine/instantiator (1.0.5): Downloading (100%) 
 - Installing phpunit/phpunit-mock-objects (3.4.3): Downloading (100%) 
 - Installing phpunit/php-timer (1.0.9): Downloading (100%) 
 - Installing webmozart/assert (1.2.0): Downloading (100%) 
 - Installing phpdocumentor/reflection-common (1.0): Downloading (100%) 
 - Installing phpdocumentor/type-resolver (0.2.1): Downloading (100%) 
 - Installing phpdocumentor/reflection-docblock (3.1.1): Downloading (100%) 
 - Installing phpspec/prophecy (v1.7.0): Downloading (100%) 
 - Installing myclabs/deep-copy (1.6.0): Downloading (100%) 
 - Installing phpunit/phpunit (5.7.19): Downloading (100%) 
 - Installing codeception/base (2.2.10): Downloading (100%) 
 - Installing codeception/verify (0.3.3): Downloading (100%) 
 - Installing codeception/specify (0.4.6): Downloading (100%) 
symfony/console suggests installing symfony/filesystem ()
symfony/console suggests installing symfony/process ()
symfony/browser-kit suggests installing symfony/process ()
symfony/event-dispatcher suggests installing symfony/dependency-injection ()
symfony/event-dispatcher suggests installing symfony/http-kernel ()
phpunit/php-code-coverage suggests installing ext-xdebug (^2.5.1)
sebastian/global-state suggests installing ext-uopz (*)
phpunit/phpunit-mock-objects suggests installing ext-soap (*)
phpunit/phpunit suggests installing phpunit/php-invoker (~1.1)
phpunit/phpunit suggests installing ext-xdebug (*)
codeception/base suggests installing flow/jsonpath (For using JSONPath in REST module)
codeception/base suggests installing phpseclib/phpseclib (for SFTP option in FTP Module)
codeception/base suggests installing league/factory-muffin (For DataFactory module)
codeception/base suggests installing league/factory-muffin-faker (For Faker support in DataFactory module)
codeception/base suggests installing symfony/phpunit-bridge (For phpunit-bridge support)
Writing lock file
Generating autoload files
> yii\composer\Installer::postCreateProject
chmod('runtime', 0777)...done.
chmod('web/assets', 0777)...done.
chmod('yii', 0755)...done.

Если Вы хотите установить последнюю нестабильную версию, выполните команду:

composer create-project --prefer-dist --stability=dev yiisoft/yii2-app-basic basic

После этого приложение будет доступно по адресу http://host/path_to_yii/basic/web/index.php, например на локальном сервере с установкой в корень web сервера:

http://localhost/basic/web/index.php

Если страница не загрузилась, проверьте, что установлены все необходимые модули и ПО, перейдя по адресу http://…../basic/requirements.php или выполнив в консоли

php basic/requirements.php