Question Brand New G2 - What to do?

Ok, so I am not new to ROOTing and ROMing. I came from the Galaxy S3 which I always changing things up on it. Now, this G2 (LS980), is a whole new ballpark for me.

1: No removable battery (that's ok)
2: No external memory... (How can you download a ROM and then Wipe everything before install, and still have the download???)

I would really like to try the d3rpG2 ROM but I am a tid bit nervous to do anything on this device. Compared to what I am use to.

I have seen a few post of people losing everything in a wipe (lost downloaded rom), how do you avoid that without having external memory?

I have seen all the post on how to get ROOT and Recovery but to me its kind of confusing (for this phone that is).

So like, is there a nice step by step guide....? or something? I know that's asking for a lot, but this phone style is way new to me and I am trying to learn as much as I can on it.

Many thanks to any helpful replies!!
Phone: Galaxy S3 i535
Rom:
Kernel:
Baseband:
Build:
Recovery: