Early Schmidt and Bender Scope Knowledge?

[Lashenden]

I have an early Schmidt and Bender OEM scope ('Frankonia' branded elevation turret cap) hanging around for years and have at last found a potential use for it. It has a 26mm dia. steel tube, 40mm objective lens, A1 reticle, no windage adjustment, overall 30cm long, probably 4X magnification but no marks to confirm. Under what I just referred to as an 'elevation turret cap' but might be some kind of BDC (what's the difference?) is a small knurled aluminium dial with a '0' and +/- hashmarks and a white reference dot. I don't have any experience of mounting, sighting or using a scope of this vintage. What do I need to know? My ambition only goes as far as achieving a 100m zero with the scope on a Swedish M38 already fitted with PH bases by a previous owner. I do already have a set of windage adjustable Parker Hale 26mm mounts. Help, please!