Hi and welcome
Best place to start is here: viewforum.php?f=13
if you are intending to play using PCSX2 emulator.
Note: Unless you have a JAP PS2 or a modded PS2 that can play JAP disks, you will need ripped .ISO of the JAP game disks. US or PAL versions WILL NOT WORK
with OBSRV.ORG. It only emulates the original Japanese KDDI servers.
Warning: It can take quite a bit of work to get everything running if you don't go the JAP PS2 or modded PS2 route, but definitely worth the effort once you get online!
. If you have problems with the process just ask in the obsrv.org chatbox on main page. Usually somebody there can help out. All the tutorials you need are available or linked to in the forum so have a look there first, but don't be shy to ask in the chatbox for somebody to point you to the right info if you are struggling
Hit me up for a game if you see me online. Always happy to help out those learning or relearning this great game