Welcome Spodgetastic!
I find it hard to read two staves at once (working on that skill...but it's hard!) so if I want to play a fully notated piece I usually have to memorize it a fair bit!
The way I do it is break it into chunks - first get an idea of the overall form - how many sections, repeated / similar sections etc. Then I work out the harmony and write in the chords and try to learn the chord progression - so the chords act as 'signposts' and I can remember a little story of how the chords go. That's also useful because then if I get stuck on the specific notes I sort of have the 'gist' of it and can (hopefully) make something up rather than have to grind to a halt. Then learn the actual notes - just a couple of bars at a time. Just do it over and over again for hours. I've started trying to learn a piece from the end backwards so that as I play it all the way through I get to more familiar parts and to avoid that thing where you know the first bit really well and the end is always more ropey.
But to be honest I don't play fully notated music that much! I want to get better at it but it's more hard work than fun for me right now unfortunately.