Help a noob! Ski boot/binding

I recently bought these old Normark cross country skis in hopes of better enjoying the huge snowstorms we've had lately. Unfortunately I don't know the first thing about skis, and the sole came off of one of my boots within minutes of first using them (pic attached of unbroken boot). I can glue/tape it for now, but I'd like to replace them eventually with something better fitting anyways. How do I know which boots to buy?! I've deduced that I have 3 pin bindings, will any 3 pin boot work with them?

TLDR: I don't know what kind of boots will fit my bindings. Any suggestions?