[Q] Need Custom Bootloader & ROM "How To" Help topic

Hey. After spending hours trying to discover a working method to root my Verizon Samsung Galaxy S4, I've succeeded. Now, I want to try to install some sort of bootloader like TWRP or something so I can install a custom ROM. What do I install and HOW do I install a bootloader? I'm confused. I also want to install the the latest CyanogenMod for it. I think I can do that on my own after getting a bootloader installed on my phone, but what file am I supposed to be installing is the question. Thank you for any and all help. This is my first smartphone, so I'm trying to figure this out.