Characters and campaigns?

Trying to understand how this site completely works.

Are characters not specifically tied to a specific campaign? just to the player?

how does a GM create NPCs?

If a Character isn't tied to the campaign directly, but to the player, how does the GM have access to dole out Experience?
First, you must create your campaign. As a GM, you will then invite characters to join your campaign. You can do this on the "Members" tab either by inviting people on your EW friend list or simply by entering their email address. The system will then send them an invite with a link to your campaign and the code word to join. Once they join, you'll have the option to assign EXP to them.

You create NPCs in the WIKI of that name. Go to WIKIs, then to NPCs, then hit the "Add NPC" button.

Hope this helps!
It's not letting me create characters. If I enter so much as a name, I get an error message. It's been this way for a long time so I assume this isn't getting fixed. I have tried it with three different browsers, and made I have permission to save additional characters by deleting an old one (whom I would have "retired", but that also led to an error message.