you'll get hot when riding and sweat a lot. it is better and more comfortable to wear a performance shirt than it is to go bare-backed. the sweat dripping down your back, chest, and sides is kinda uncomfortable.
you can get on like you would a normal bike - that's how i get on.
if you're going to train for an hour, get enough water for that hour.
i like downloading documentaries and other like-shows and watching them on my laptop when i get on the trainer.
i also get on the trainer in the winter when i stop riding on the roads. i just grind my old rubber down and get a fresh pair in the spring.