Microsoft Excel – Replaces the value of a column

My question is how will I replace the value of a cell base on its header?

here are my sample data, i want to replace all the "x" value so far (well based on their designated column please sample raw data sample

the exit will be like that well see the second photo
example of data output

I do not know how to create a macro for that. I'm just wondering about adding the macro in the sheet itself so that it runs automatically without clicking a button whenever I want to change the value.