Really you should have asked these questions before you actually got the animal, but anyway...
can i pick him up - Yes, so long as you are gentle. Only hold him for about 15 minutes at a time so that he doesn't stress out too much. You might like to leave him alone for the first few days to give him time to settle in.
how much soil do you need at the bottom of the tank - I don't think it matters much... say an inch or two?
how many times do you clearn out the tank - You can spot-clean it every couple of days (by 'spot-clean' I mean remove any visible poo etc.) and clean out the whole tank once a month or so.
what does it mean if they in a ball - Either that they are asleep or feel threatened.
do you give them water in a bowl - Not much need to do that since they will get a lot of moisture from their food and you should spray the tank down with water once a day. They will drink droplets that form on the tank sides or on any decor.
why will he not eat apple - First off you haven't had him very long and he may still just be settling in. Also, they need to be given a variety of veggies. Yours may just not like apple! Tryhim on lots of different foods to find his favourites. Try finely chopped lettuce, tomatoes, cucumber, grapes, melon, peaches, banana, finely grated carrot and squash. There are loads of veggies to try him on! You should also get some reptile calcium powder or some cuttle bones and grind it up to sprinkle lightly on his food occasionally to keep his shell strong.
he not moved from being in the ball for like 4 hours - He might just be asleep! Or he could be stressed out. Make sure he has plenty of hiding places in case he feels threatened.
how much should a spary the tank with water - This is more or less common sense. Spray enough so that the tank sides and decor have a few droplets on them. Also make sure the soil is damp to touch.
i put some moss from my pot in the tank i have seen a bug on him will it harm him - Depends what sort of bug it is? To avoid stuff like that happening you can pour boiling water over moss before putting it in the tank to kill any hitch-hikers. Then just wait for it to cool before putting in his tank.