Copying formula across columns where row sumber remains static

I am having a problem copying the formula below:
=((C3-'Trend Data Paste'!C2)/'Trend Data Paste'!C2)

I need to copy the above formula from cell B3 across to cell D3. the formula should then read:
=((E3-'Trend Data Paste'!C3)/'Trend Data Paste'!C3)

I then need to copy that formula from cell D3 down through cell D55 & it should read as follows:
=((E3-'Trend Data Paste'!D3)/'Trend Data Paste'!D3) in cell D4
=((E3-'Trend Data Paste'!E3)/'Trend Data Paste'!E3) in cell D5 and so on.

I then need to redo this 12 more times. The only way I can get it to work is to manually type this formula. I would rather not do this 624 more times.

I'm sure that my problem is with the original formula, but I am an excel novice & cannot figure this out on the help function. Any suggestions would be greatly appreciated!!