Every Video in the YouTube playlist has its own branch. The master branch always contains the latest code.
If you want to look at the code of the "Laravel 8 - Validation" video, then checkout to that branch specific for that video and you will be able to see all the codes there. E.g.
git checkout validation
Run the following commands to install the project and get started
git clone https://github.com/Laratipsofficial/laravel-basics.git
cd laravel-basics
composer install
cp .env.example .env
php artisan key:generate
php artisan serve