You need a UV light for them to process vitamin D3 which will aid their growth and promote a healthy shell.
You need a heat light to simulate the sun to encourage them to come up to bask.
You can buy combined UV/Heat bulbs called MVB or Mercury Vapour Bulbs.
These need to be over a basking platform as UV light will not penetrate water. The basking platform must be big enough for them to get completely dry and out of the water.
You will not need a water heater for anything other than hatchlings. Ideally you want your water temp around 22*C and your basking spot around 32*C
For further reading try The Terrapin Tank - www.TerrapinTank.co.uk -
and Welcome to ATP
Obviously care varies slightly from species to species so pick one you like then do all the research you can.