Forgive if this is too basic of a question but:
I see lots of hints/tip to get better prints. Say I make a change to improve removing supports. Where/how do I save them?
I download a bunch of files. I just don’t want to have to make the same changes after each download.
I am not entirely clear on your context here but you can modify print profiles for your filaments to save these. You will just need to ensure you are using those profiles each time you slice something.
Regarding the settings like quality, supports, etc, I believe this is done by utilizing the save button next to the layer height/preset dropdown just above your quality/strength/speed settings area.