Find closest multiple of $256$ to $1000$. We see that $3 \times 256 = 768$ is the nearest. Now subtract $768$ from $1000$ to get reminder $232$. Add $3$ to quotient.
Find closest multiple of $256$ to $2320$. We see that $9 \times 256 = 2304$ is the nearest. Now subtract $2304$ from $2320$ to get reminder $16$. Add $9$ to quotient.
Since $16$ is less than $256$, stop the division. The reminder is $16$. The topmost line $00039$ is the quotient. Remove all zeros at the start of the quotient to get the actual quotient $39$.