How can I install a custom ROM?

[Meg Faulkenberry]

I just rooted my S3 (SPH-L710) using Kingo last night and I want to install a custom ROM, preferably Omni ROM if I can. Please keep in mind that I'm a SUPER beginner; I've been trying to find a way for like the past two hours and feel like I'm reading Chinese... This stuff could not be more foreign to me.

Any genuine help would be appreciated <3

 

[UJ95x]

Welcome to Android Central
Are you on 4.3? If you are, you can use SafeStrap for custom ROMs, but you'll be limited to TouchWiz-based ROMs, which means no Omni