Ok Ive worked out where i was going wrong with the syntrax of the formula, and this is what ive got so far:
=if(B5:B51=3,1)
But Excel doesnt seem to like the B5:B51 part of the Formula, and also at the moment the formula (if it works) will just change the cell value to 1 and not Add 1 to it, +1 doesnt work? What would be the correct way to put it?