Hi and welcome. One thing thats for sure is that you will learn and it will be a steep learning curve, before I got mine I hadn't even ever changed a wheel, now I can weld and have a garage full of tools and no spare weekends. Have a search for the 300tdi workshop manual online you can download it for free, I don't rate the Haynes manual, first thing I brought and used it once, now brought myself a paper copy of the workshop manual and it's worth it's weight in gold.
Get under with a wire wheel and a hammer, check the chassis for rot, don't be shy to give it a good whack to find any weak areas and if you find any sort them sooner the better.
Everyone is very helpful and knowledgable about pretty much anything you will ever have a problem with! Someone will always help and don't be afraid to ask.