Neeed some help.

[H3nk]

Hi there, I've got an Avalon with built in Cgminer, so far so good.
I also have an account at cex.io with a 9 digit ID.
Can't get hold of the previous owner of the rig, but with his Pool1 worker ID XYZ.1 and password 123456 it is mining.
Anyway, the big Q is, what Pool1 worker ID should I use to start mining, I know it sounds like a silly question, but I'm absolutely clueless.