Using 'Or' to return a value

[Uncle heFTy]

I am trying to create a table that is based on the following:
There are three conditions; A, B or C and if a cell contains either of these then I want to return a different value (another cel) for each so, in plain English - If the cell contains A then return the value in cell X or if it contains B return the value in cell Y or of it contains C return the value in cell Z and if none of the A, B or C is present return 0

No matter what I try I cannot seem to get the formula right.

Can someone help, I am struggling here

Uncle H