I'm certainly not the best at this, but I guess I'm not doing that badly since I've had to give away a ton of worms twice from over population.

When I brought home the bin, there was some starter scraps, then on top was some torn/shredded newspaper mixed in with some hay and dirt. Sprinkle that with some water and leave it alone for a week (they stressed this quite strongly). What they taught me to do was to put the scrap in one corner, then the next week another corner, and so forth so you give the scraps some time to be broken down. Make sure to keep everything covered, though.

If you think it's too moist, try to get as much cardboard out, and maybe put some shredded newspaper in there. If it's too moist then they'll try to crawl on the sides to escape the moisture. Can't be too damp, and can't be too dry.

Try putting a potted plant on top of the compost bin's lid. It should absorb some of the heat.