My advice is to check out some p1999 videos on YouTube. Found this one pretty quick and it has some details of setting up your UI
https://youtu.be/-OWNSczauVE
Also check out the wiki,
https://wiki.project1999.com/Main_Page. It has very useful information including maps, beginner guides for each starting town, etc.
Alt+O will bring up your options menu. Check out your key binds and consider reworking them (definitely move “attack” from the A key, lest you smack you guild master and get vaporized. Yes I did this on my first char.).
Lastly take it slow and have fun. Chat with people, tell them your new, and get out there an explore!