Search Page Sorting, How to change?

Hello,
On the Search page I am given the opprtunity to “Sort by” several options … (NOTE: see attached image).

These options are really irrelevent and I would rather sort by categories that I have created.

I see that on the Search Page options that you can add some other sorting options but am not sure how to connect them to certain categories.

Also, how do I delete the ones that are there, the ones that are irrelevent to my site?

Thanks!