Set up CI/CD pipeline from Gitlab repo to my server.

Hello, I have a Ubuntu server running on DigitalOcean. It is hosting multiple websites using nginx and pm2. I have a few Gitlab repositories that contain the code for these websites. I would like to set up a working CI/CD pipeline using Gitlab's built in features, so that when I push code to the remote repo on Gitlab, it tests my code, and if it passes, it will push it to my live server. I need this to work for each website/repo. There's seven total I believe. Or you can just do it for one and provide me the steps to recreate it for the other websites to save time/money.