So this is a number pattern puzzle. Numbers going from left to right will have the same number pattern. In the first box, 5 -1 =4, which is the number to the right. 3-1=2, which proves our theory correct.
Flipping the direction means you will need to change a positive number pattern to a negative or vice versa. Using the same example, if instead of going left to right I want to go right to left, I will use a +1 instead of a -1 (for the first box)

Then when we look at the 3rd box, the pattern from left to right is +4 (7+4=11)
Means that the missing number is 4+4 also.
The pattern from down to up is -3 (7-3=4) so doing 11-3 still gives us 8. Proving we are correct.