Hi everybody,

I have a simple problem i guess, but can't solve it.
I just want that one or (some) cells just manually can be filled with the words "BFW" or "BF" . If cell is filled with spaces or any other value it must
give an error (such as you have to fill in just "BFW" or "BF". I know this can be done in section data valadition, but no luck yet. I have tried different formules, but no luck. Can someone help me?
Just a beginner with Excel

Greets Rob