Well you've got some nifty multimeters, or a good mate to lend them to you.
You cam read up a lot and pick up a lot but the basics still apply and they're pretty straightforward and simple, if you think of the battery purely as a store, or a simple bank account, you can't take out more than is put in, you can only spend the money once and then it needs replacing if you want to spend more.
If you want more info, details, and fact sheets, links, on batteries and VW's system PM me.
There no trouble with learning for the first time absolutely everyone has to, but some of us struggle to retain or remember what we've learnt, and relearnt. 😄 I only learnt about VW's battery 'coding' stuff when I got a new battery for my wife's Fabia Mk3, all PITA stuff to me.
Don't worry about battery serial numbers and battery make that was just for VW's sake and often the factory hasn't bother with the serial number just put a string of ones (1111111111) and all you need do is increase that number by one (1111111112). Also you need to change the battery type from EFB to fleece (VW for AGM) and alter to 70 (Ah). As with all computer data input or 'coding' be very careful to check what you've typed and double-check it before committing to the program. See the example for my wife's car done by a Briskoda member on his OBDEleven. The battery manufacturer was a three letter code but you can just leave it as before. AFAIK Bosch is a Varta so I and you could put in "VAO" AFAIL VW's code for Varta (but mine has been fine left with "Bosch").
You might get the previous battery back for useful use, be interesting to see, as I put the secret is time and patience (which many don't posses, one or both) go as low (amps) slow and long (many hours or day or days) as you can, always fully charge the battery even if it means doing it in a couple of stages if you don't have time or need use of the car.