A breakpoint will cause the code to stop running and you can then test some of the values etc.
Then you can use the f8 key to move forward one line of code at a time.
To create a breakpoint move the cursor into the area to the immediate left of the line of code.
Click in this area and a round marker appears and the line of code is highlighted.
When the macro runs, it will stop at that line (the line is then highlighted in yellow).
If you need to know about an object or a variable, select it and right-click and select 'Add Watch...' and OK from the dialog box. The selected item can be viewed in a new window that opens.
I can't test any of this for you as I don't know what the items are = what is CMP1 and where is it - is it in a user form and is this in Access or Excel.