Find closest multiple of $18$ to $51$. We see that $2 \times 18 = 36$ is the nearest. Now subtract $36$ from $51$ to get reminder $15$. Add $2$ to quotient.
Since $15$ is less than $18$, stop the division. The reminder is $15$. The topmost line $02$ is the quotient. Remove all zeros at the start of the quotient to get the actual quotient $2$.