First rule of asking for help, don't ask for permission to ask. If we're going to help we'll need more information on what you want to do, as tasks can range anywhere from trivially easy to outright impossible.

Egosoft wiki's page on modding.[wiki.egosoft.com]
Universe Creation guide[github.com]

These are the only two things I can really find I'm afraid. I'm trying the universe creation myself but stuck at the stage of putting gates into existing sectors to connect my new one to the universe. You can teleport there with cheats but right now its technically unusable.

I'm trying to find the X Catalog Tool, which supposedly is available through Steam, but no go. I'd rather not sign up for an Egosoft forum account if I can avoid it.