The circle of 5ths is a way of going through all 12 notes on the scale so that each note is a 5th below the previous one.
Never mind why you need to learn it right now, just memorise it! It won’t take you very long and it’ll be incredibly useful very soon.
1. Memorise the circle of 5ths, starting on C, then going up a 4th, down a 5th, and so on, until you get to C again. Remember that you change colour between the F’s and B’s.
2. Now memorise the circle of 5ths, starting and finishing on C, but going down a 5th, up a 4th, etc., this time.
3. Finally, get used to going through the circle of 5ths those 2 ways, but starting and finishing on notes other than C.