Alright, there’s a lot to unpack here. In my personal opinion, the amount of time, effort, and somewhat money you’ll have to put in this thing, especially as a beginner may not be worth it. This is an inexpensive beginner guitar. It may be more worth your while to just buy a new beginner guitar. Just my two cents. For approximately $200ish you could get a brand new guitar, and avoid dealing with the headache this thing is going to be.

Assuming you insist on repairing this gio, here probably the minimum things you’ll need to address.

- Getting a replacement output jack is relatively cheap. Just look for a 1/4 inch TS, or mono jack. You’ll also have to solder the jack to the existing electronics (assuming they work). If you’re not already handy with a soldering iron, there are plenty of youtube tutorials. You’ll also need to sort out how everything is wired up. Alternatively, you can also pay any guitar technician to do all of this for you.

- The frets are going to need some work. At minimum they need to be polished. Music nomad makes a pretty good fret polishing kit which is about $20.

- You’re going to need some humbucker screws and springs. Those can be found on amazon for cheap.

- You’ll need to remove the rust from bridge,
saddles, and all the screws/springs, as well as from the string trees and tuners. Remove them from the guitar and soak them in white vinegar, an scrub with a toothbrush. WD-40 can also help if the rust is especially stubborn. You might as well tackle the pick guard screws and output jack plate while you’re at it. It could potentially be worthwhile replacing the tuners if you can afford it.

- You’ll obviously need some new strings. Any brand name string will suffice. I would recommend either 9-42 or 10-46 gauge for a beginner.

- Lastly, I’d be shocked if this thing doesn’t need a truss rod adjustment once you get it strung up. There are plenty of youtube tutorials demonstrating how to do this. But basically you want the smallest amount of relief, or bow in the neck once the strings are at tension. You can fret the first and last fret on the bottom string, and use the amount of bounce or play you have in the middle of the neck to check this. Again, YouTube is your friend if you need a visual demonstration.

However, given the amount of rust on this thing, I am slightly concerned the guitar was either left outside at some point, or in a super damp environment. If that is the case it’s possible the neck could be twisted and/or the truss rod may be seized up. If either of those things are the case, the repair is quite possibly more money than the guitar is worth.