63 ÷ 3 = 21 R0
No problem, we've got 63 and 3 for the division.

Step 1:
3 goes into 6 2 times with a remainder of 0.
Write down 2 as next digit of of the result. 
Result so far: 2
Subtract 6 from 6 to get 0.
Bring next digit (3) of the dividend behind the 0 and repeat the process: 3 / 3

Step 2:
3 goes into 3 1 times with a remainder of 0.
Write down 1 as next digit of of the result. 
Result so far: 21
Subtract 3 from 3 to get 0.

The final result is 21 with a remainder of 0.