As a TOTAL noob: appreciate the easy explanation! Waiting to do this myself, but have a few quick questions first. I've done a lot of reading up on rooting but I'm still not entirely clear on a few things so I'm hoping someone can explain it to me like I'm five:
1. Can I accept over-the-air updates from Sprint on a rooted phone? i.e. when they push Android 4.2. If not, do I unroot and reroot to update? Do I have to uninstall everything?
This is not going to be a straight up yes or no answer. If an update comes ota to your phone, you will be able to receive it providing you:
1. reflash stock recovery before accepting it.
2. haven't flashed a custom rom
3. haven't removed any required software. The ota will look for certain software and files. if the required software and files aren't present the ota will fail
None of this should concern you though. There are ALWAYS ways to get the updates while being rooted
2. Is there something I need to install after doing this? I previously rooted an HTC EVO and remember having to install Superuser immediately after. Anything similar here? Looking to ultimately run wifi tether so any advice toward that end would be greatly appreciated.
These instructions seem like you are doing many things. You aren't. There are really only 5 steps. I just broke all the steps down in detail. Really all this is:
1. Downloading all the files to your computer
2. Installing your Samsung Drivers to your computer
3. Copying one file to your phones sd or external sd card. (Team_Epic Root_From Recovery)
4. Flashing CWM Recovery to your phone with Odin.
5. Flashing TeamEpic-Root-from-Recovery-v5.zip with CWM Recovery
The Team Epic File that you are flashing in recovery installs superuser, busy box, and in addition removes two files needed to make recovery stick.
3. I'm a little confused about rooting/flashing and some basic definitions. Are they the same thing? I hear a lot about CyanogenMod - what is it and is it coming into play here?
Rooting is really nothing more than giving you the user, the right to access root or system files. It has very little to do with flashing as you can flash updates with stock recovery.
Flashing is simply installing something in a tar, img, or zip format. tar files are flashed with Odin, zips are flashed from recovery and img files are flashed or pushed with adb (Android Debug Bridge)or fastboot.
Cyanogen is a rom. roms are very simply the phones operating system and user interface. They're called roms because their files are kept on read only memory. There are many roms out there for our phone.