Explain something

Can someone explain or advise me about calories please.. ive not long since set up the app and am very confused about the calories readout... my base goal is 2330 and today my food intake is 1115 but after a 4 mile walk i have burnt 1532 calories leaving me with 2747

It just doesnt make any sense to me at all... sorry if im being thick but can anyone please explain it in plain english that a 61 year old can understand