Allright, open up the server window. Type "create account admin, name, password" where name and password are your own account names and passwords respectively. To create normal users just use "create account user, name, password" where name and password are their names.
Okay so you've got the server loaded and have your own account now close the server. To log in first you need to edit blakserv.cfg and meridian100.aq.com (all instances) to meridianX.aq.com where X is the server number you want to label yours as, usually it is 3 digits, I'm sure you could duck around with that. Then edit your hosts file as described earlier by me *first post I think*. Finally reload your server.
So now you've set up your server. I'm doing this part off the top of my head, considering I have no client on my comp atm:
To log in open up your m59.exe and click on connect, fill in the proper information including the server number you chose. Now after you click connect you SHOULD get a dialog box that has <new character> in it. Click on ok or next or w/e the accept thing is there and proceed to create your character.
Voila, once you're done you should be in game so feel free to screw around with GM commands and feel free to be brave and dig deep into the server files figuring out what everything does.
And yes it is possible to create your own spells and areas. And yes it is possible to hand make a resource/room/art editor for Meridian 59, it was in the works way back, project probably died. No clue.
Good luck sirs.
for me....