I made a new game a while back and then made a game with all the soundtracks in it. So how am i meant to make a link from one project to another one.

You can just copy the URL of the project (it appears in your browser's address bar), and paste it into the other project's notes or instructions. It won't be blue and clickable for you since you can edit the description, but it can be clicked by anyone else (or if you log out).

copy the URL and paste it in the notes and credits

thanks for the help