OK, let's do this. We've got 893 and 632, and we're subtracting the second number from the first.

Step 1: We'll start by subtracting the digit 2 and the borrow 0 from 3 in column 1 and get 1.
1 is the first digit of our result.

Step 2: We'll start by subtracting the digit 3 and the borrow 0 from 9 in column 2 and get 6.
6 is the next digit of our result.

Step 3: We'll start by subtracting the digit 6 and the borrow 0 from 8 in column 3 and get 2.
2 is the next digit of our result.

So, 893 - 632 = 261.