Ok here are some of your questions answered...
1)
What level would one begin?
You start at level 1. I'm not sure how Image got the XP set up
2)
How do you put yourself in a Guild?
Guilds are not assigned. You gotta be accepted into a guild thats been started, or create your own.
3)[/i]
How do you advance within your guild?
Thats up to however the guild your in decides.
4)
Can you create a guild by yourself?
You can start a guild...dunno exactly what you mean as if you have to have other people in your guild or you can be in the guild by yourself.
For more information...i'd suggest you'd go to Image's GuildWar Forums at...
http://www.dmicale.com/forums/index.php?c=3