Where do I change the "priority" settings?

[John David Chapman]

Hi, can someone tell me where I set the priority levels please?

I have three customers who will use RT, thus I set up 3 different queues, and I *assume* I should use the priority setting to correspond to the SLA.

(I ordered RT essentials of Amazon, and they have told me they no longer have it   anyone else know where I can get this book?)

Thanks