Not the hardest species to raise by an means but also not the easiest.
They tend to be shy and sometimes develop shell problems.
Since he is small you will want ot get your hands on asmall (25 - 50 watt) aquarium heater and warm the water to 78 - 80 for the first six months or so.
After that, assuming he seems healthy, you can likely dispense with it unless you house is unusually cold.
Adding water plants, live silk or plastic will help the little gut feel secure.
Keep the water clean.
Do more water changes than you think you need to do.
Despite that its acommonly suggested method of good turtle housekeeping, don't try to feed it outside the tank. This species is usually too nervous for that to work well.
As for food i'd try live blackworms, pre killed guppies, tiny crickets, bits of cooked shrimp and cooked fish (any kind you would eat). Keep up with pellets as well.
As he grows try to add bits of fruit and water plants. Some miss maps will consume dark green leafy vegeatbles and carrots in small amounts as well but the staple of the wild diet seems to be insects.
Adding powdered calcium with D3 supplement to the water and to any food it will stick to is a good idea.
If the water is clean, the basking spot warm, hiidng places abundant and handling kept to a minimum (only when necessary for cleaning) it should do fine. It should not grow too fast. Bu in a few months the shell should begin to harden or you can expect that there is something wrong.