In order to install module, you can do it two ways:

Install By Composer
    Take clone
    run composer require sbdevblog/module-sbdevblog-customer
    Run necessary magento commands like setup:upgrade, di:compile, static-content:deploy
Install From App/Code
    Clone and Just extract zip and paste SbDevBlog/Customer directory inside app/code
    Run necessary magento commands like setup:upgrade, di:compile, static-content:deploy