I don't fully understand Amps
The ampere is the unit we use to measure electric current. Current is the flow of charge. 
Charge is conserved. Charge is not created or destroyed. That gives us Kirchhoff's Current Law (KCL). This says that in a lumped circuit (a circuit whose physical dimensions are much less than the wavelength associated with the highest frequency signals being considered), where 3 or more wires meet the total current in to the junction (aka node) is zero. 


You can use KCL to find how the currents in your circuit add up to give you the total current required from your power supply.