Where can I get a reference manual?

When I was younger (IE when I didn't have children) and had a 1990 Westy, I
had a factory manual, purchased for ~1$150; but I think I let it go with
the van.  Shoot me now.  Back then, I didn't mind that I didn't know what
all the bits and bobs were for.  Now, with kids, can't stomach not knowing
what everything is: cylinders willy-nilly here and there, vents,
lines-gallore, little throttling valves -- I gotta know, man.  Know what I
mean???
What is all that stuff???  What am I going to do when it breaks down?

Warts sprouting,
Gabby
1986 Westfalia, GL

PS -- What does GL refer to, anyways?