I generally tighten the trainer down until it touches my rear wheel and then give it 3 or 4 more turns. You want it to give you some resistance, so it should indent the tire a little bit. If you don't tighen it down enough and the tire slips an you can wear your tires out faster.

Some trainers have multiple resistance settings, some get harder as you pedal harder (fluid types). Most indoor trainers are pretty noisy - especially if they are wind trainers, magnetic trainers are a little quieter, so are fluid trainers. Don't worry if its loud.

I use my trainer for all kinds of workouts. Sometimes I spin in a small gear, somtimes I do big gear drills. I do find that the same hr zones feel more difficult when indoors - I think that it may have to do with over heating. I usually use a fan inside.

If you feel like you are pointed down you can put your wheel block up on a book or two. You can also do this if you want to somewhat simulate hill climbing. Some wheel blocks have different levels that you can set the wheel on by turning the block.

Hope that helps a bit - have fun with the trainer!