Multiple Timestamps on same Google Sheet Tab

I am trying to work out what script is required to have mutliple timestamps on one tab however each one i have tried doesnt work for me. I am new to this.
When text is added to column 2 I need a timestamp in column 1. When text added in 8 I need a timestamp in 7. When 15 which is a checkbox, a timestamp in 16, and when 18, timestamp in 17. Is this possible to have so many?
The sheet tab is called June 2021.