I'm rusty...how do I re-associate what files open in what program?

[KnobsNSwitches]

I'm rusty in System 7, I guess, my LC 550 isn't opening .sit files in Expander, despite me trying and reinstalling a few different versions. Opening Expander and choosing the file does work. And I'd like to update text files to open in BBedit instead of SimpleText. I can use ResEdit to change type/creator codes for the text files, but how do I set a...default program for such things?

 

[KnobsNSwitches]

Ha, there is a program called Text Changer included with some versions of BBedit that will update the creator code any text docs it finds in a folder you choose.