I'm not going to be a lot of help here... I'm neither a quad nor a Spectrum radio guy... so I can only help by pointing in some directions at best.
First for the disclaimers and downers... If you are a beginner, this is not a project for you to start off with. I'd only recommend doing mod's on something like this if you are experienced in both airplanes and multicopters ... as well as customizing and modding both. If that isn't you, then put this project aside until you have some experience... ok, probably a lot of experience. The RC hobby is great to get into, but you must start ( if you are a beginner, I have no way to know so I'm covering this first ) with a more beginner friendly aircraft, car, or boat. ... Now having said all of that...
I was able to still find a manual online despite the company that made this being out of business...
The main manual, the quick start guide.... and a bonus conversion guide that actually may be of use for the radio setup portion although it also covers installing and using a custom FC also. I suspect the manual and quick start guides will be nice to have, but I skimmed through them and didn't see a lot of useful info concerning how to configure the FC or radio for instance. The conversion guide will likely have a lot of info that doesn't relate to the installed FC, but hopefully it will help at least in general with setting up the radio even if it may not be identical to your own.