I wish to modify a behaviour from products page. When clicking on vendor name, to redirect to external domain. Till now I have understood that, if the file contains {hook}{/hook}, I can modify the behaviour by adding a separate hook file (pre,post,override).
I am working on a custom theme, and the file, where I want modifications, doesn't have hooks in it. So, the modification that I expect, I have to manually code,
-> first by adding {hook}...
-> then creating a (post,pre,override) file.
Problem that I might run into is, if the theme will have upgrades in future, my custom codes/modifications will be lost.
So, my question is what is the best approach to work on modifications?