Hi
@Jamie2.0 and welcome to the Forum. You seem to be wise in the world of VW so let the fun begin. A word of warning - we members are very good at spending other member's money, but with the aim of spending it wisely. So please don't ask for advice and guidance as there are many people with extensive experience,including Trade Members, who will help.
As for van lining try the threads by
@Colinlp and
@xpfloyd and the trade members
@slidepods and
@Absolut5 for an overview of great DIY and Trade conversions and lining, plus other aspects of fit out.