I'm new to this too but i do know that if its got all those glued on rocks on the top then you need to take all that stuff off and make sure its in the right kind of soil & put it outside in the sun like the big azaleas are or its going to die. They make people think they are indoors plants when they are just regular trees that growth was stunted. I don't know about the azaleas but the trees you need to plant them in special bonsai soil & when you buy them in the store they are in regular potting soil so that's important.

Azaleas are pretty robust as long as you know how to treat them. First and foremost, do not over water them. This is relatively true for most bonsai but especially for azaleas. Resting water in the bottom of the pot will kill the roots and cause major damage to the entire plant, but it does appreciate moist soil so its a balancing act. Watering 2-3 times per week is usually good. Make sure the tree is outside, as all bonsai(unless it's a tropical or semi-tropical species) are meant to be outdoors as KEG222 correctly pointed out. Azaleas are sun-loving plants which require ideally 6-8 hrs of direct sun per day.
Fertilize your tree with a half strength 20-20-20(miracle gro) fertilizer every other week during the summer months. Keep in an area between 35-50 degrees during winter months, do not expose to freezing temps or it will die.
As far as trimming goes, do what you like to make the tree your own, but keep in mind:
The balance of foliage to roots is very important in trees, for example: if you trim most of the leaves of a tree you must, in turn, trim most of the roots to keep the root to foliage ratio in balance. Minor aesthetic trimming can be done at will. To simply keep a tree the same shape and size it is now, simply pick off any new growth, this WILL NOT harm the tree, it will only focus the tree's growth into the trunk and branches, which will give the tree an older , more developed look over time which is the point of bonsai. I hope this information helps, happy pruning.