I guess my earlier questions were considered too noobish to answer or something, but luckily after some more searching I was able to find some guides that helped me figure everything out and get homebrew running on emuMMC. This guide:
https://www.scenefolks.com/pages.php?page=4210 is good for getting emuMMC set up with the latest Hekate and Kosmos and also tells you how to start and add homebrew. And I found this guide:
https://switch.homebrew.guide/usingcfw/installnsps/installnsps-nsusbloader for installing NSPs. Hopefully those will help out some others that are just now getting into hacking their Switches.
I do still have a question, though. On the emuMMC guide I linked and a few other sites people have said that it's a good idea to use a separate SD card when using your legit sysNAND to be safest against being banned. I'm wondering how necessary this precaution really is? I'll remove my SD card when not using emuMMC just in case, but it'd be nice to not have to do that.