When you clone the git repo you must follow these steps to run the project:
Create a Database locally
Rename .env.example file to .env inside your project root and fill the database information. (windows won't let you do it, so you have to open your console cd your project root directory and run mv .env.example .env )
Open the console and cd your project root directory
Run composer install
Run php artisan key:generate
Run php artisan migrate
Run php artisan db:seed to run seeders, if any.
Run php artisan serve
Now, your project will run. Good Luck!!