Think of Electricity as water.
The source (like a reservoir) is the potential. So if you have a Dam with a water level 600 ft over the stream below you let that water fall down a tube, that has a lot of potential, you have a lot more potential than if the water level was 1 foot above the stream below.
The current is the flow of electricity (number of electrons that pass a given point in seconds)
So if that tube is the size of a drinking straw you can have a lot of potential (volts) but very little current flow (amps). If you make that tube 20 feet across, you have a lot of potential and a lot of current flow.
If you take the water level down to one foot above the stream below but have a 20 ft tube, you have very little potential but lots of current.
The resistance is what the water runs into. If it runs into a brick wall (large resistance) the force has to be dissapated somehow. The Potential will build up against that wall and if you measure one side of the wall versus the other you now have a large difference in water flow, which is the difference in potential, which is Voltage.
Large resistance=higher voltage across the resistance
If you have a screen door at the end of the flow, you have very little resistance so if you measure one side of the screen to the other there is not much difference, therefore little potential=smaller voltage across the resistance.
If you learn this formula, you can figure out most things in electronics.
E=IxR Voltage=Current x Resistance
I=E/R
R=E/I