How to set up Gitlab with SSL Correctly?

Hello, so I followed this guide here to set up Gitlab here.

The problem comes with setting up SSL. You see, I followed this guide here to generate an SSL certificate which worked when I was setting up NextCloud.

Thing is, majority of the guides tell me how to set up Gitlab with Lets Encrypt (such as here) when I want to set up a self-signed SSL (which I did in that guide).

The thing is, the files I get when making the self-signed certificates (apache-selfsigned.key, apache-selfsigned.crt, dhparam.pem) are not the same of the ones I need (cert.pem, chain.pem, fullchain.pem, privkey.pem)

Anyone can helo me setup Gitlab using a self-signed ceritificate? I can make another self-signed certificate if needed