Complicated formular. Formular, remove text if available

Hi all,

I'm trying to create a formular that is quite complicated. not too sure where to begin. Maybe 2 scripts here to check the whole spreadsheet?

Basically there three things it needs to do.

1. On the second row needs to remove - S and add 'Small' in column 'C' Size. If possible to check if it is "clothing" as well.
2. Another script or same script formular to do the same to look for - M and populate C'with Medium.
3. A script to check the whole spreadsheet, and on row 3 remove - 38 and polulate collumn 'C' Size with 38.

That's basically it. Image below.

doc.jpg

This is it in simple terms. There are actually over 1000 rows with different values, though with a copy and paste the script(s) would populate the fields for me. Any ideas much appriciated.

If you want to "edit" on column A itself by removing the "S" or "M", it'll result in circulation error. So it's either you delete those manually or have a "helper" column.