I am trying to use the IF function to search for a certain abbreviation
across a number of different cells across several sheets. I.e. to count the
number of cells containing this abbreviation.

I have been able to use this for one cell using :

IF(D5="RAB",1,0)

I.e. if D5 contains RAB count 1, otherwise count 0.

How would I reproduce this for a range of cells?
Using the same principle :

IF(D2:D5="RAB",1,0)
However this gives me a result of 0 (when it should be 1)

Im not that experienced with excel so am I using the wrong formula or not
filling correctly, any suggestions?