Create a new repo and clone it locally:
gh repo create khm-travel/foo --public --clone
Enter the project
cd foo
Configure repo to not track WP core
touch .gitignore
Install WordPress
wp core download
Create the configuration file from the sample provided.
mv wp-config-sample.php wp-config.php
Update the configuration file with database connection details.
Install the database (if this is a brand new site).
wp core install
Otherwise, import the database from an archive.