Hello!
If you want the Column not to move you just put the dollar sign in front of the letter, and another dollar sign after the number if you don't want the row to move as well when copy/pasting formulas.
For example:
A$1$
in this case, both the row and the column will stay the same when you copy paste the formula.
A$1
in this case, the column will stay the same, but the row will change when you copy paste the formula.
A1$
in this case, the row will stay the same, but the column will change when you copy paste the formula.
For more tips in Excel and financial modeling in general, you can go
here. Hope this helps!