Advancing formulas when copying to new cell | Excel forum

I am trying to set up formulas for a simple calculation between two worksheets but having issues working out how to control the advancement when copying them.

Eg: In Worksheet 1, cell A1 should display the results of:- =(Sheet2!C2-Sheet!C3)

This works fine. However, I have other columns in Sheet 1 that need to be ignored therefor the next calculated cell should be:
Sheet1!A3 displays:- =(sheet2!c4-sheet!c5)

The problem is that because Sheet1 has columns and rows that need to be ignored, when I copy the formula it advances the reference by the number of cells on sheet 1 instead of on sheet 2.

I can lock the formula to either the row or column of sheet 2 but since they both change eventually it forces me to manually edit one or the other introducing the risk of human error.

I need function like $ that tells the formula to use the structure of sheet 2 (e.g. advance 1 column only) no matter how far it moves on sheet 1 when copied.