This is an example module with Create Admin menu and controller In Magento2
Magento2 module installation is very easy, please follow the steps for installation-
=> Download and unzip the respective extension zip and create Webkul(vendor) and Hello(module) name folder inside your magento/app/code/ directory and then move all module's files into magento root directory Magento2/app/code/Webkul/Hello/ folder.
Specify the version of the module you need, and go.
composer config repositories.reponame vcs https://github.com/webkulabhi/magento2_sample_module
composer require webkulabhi/magento2_sample_module:dev-master
$ php bin/magento setup:upgrade
$ php bin/magento setup:di:compile
$ php bin/magento setup:static-content:deploy
=> Flush the cache and reindex all.
now module is properly installed