Excel Search find and Copy

Hi,

I am very new to excel and have come to an impass.

I have two spreadsheets, both with data about my customers. Each customer has a reference number (clientbank Ref).

What i need to do is to cross-check one sheet's list of clientbank ref against the other sheet without having to type each one into the search option.

Once i have assertained what clientbank ref are the same I then need those ref to be copied to another sheet in some sort of report/table where i can use them easily.

Please help.