Any generic wheel block should be fine.
Turn the tension knob till it barely touches the wheel and then 2 1/4 turn more.
Most importantly, buy some Spinervals DVD's (Ebay is fine). They will convert the trainer from a torture machine to a fun training tool. The Carmichael Training System's 8 week Progressive Power Series is great also.
I don't have a mat (it is in my basement) but I do have a sheet of plastic under the trainer to collect the small bit of tire tread that you will eventually get and the sweat
.