OK, let's do this. We've got 3069 and 1266 and we're adding them all together.

Step 1: We'll start by adding the digits 9 & 6 in column 1 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 6 & 6 in column 2 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 0 & 2 in column 3 and get 3.

Step 4: We'll start by adding the digits 3 & 1 in column 4 and get 4.

So, 3069 + 1266 = 4335.

