Honing Guide help

OK guys so I got the side clamping honing guide from woodcraft a few months ago, I never need it until now that I’m on the plane restoration process, can anyone explain me how to set the iron blade properly to get the right angle?

I do see some information on the side of the guide but what does it exactly mean by “projection”
I’m guessing that should be the distance of the edge of the blade to the front edge of the guide, I am right?

Please I will appreciate any help you can provide me

Alonso

-- The things I make may be for others, but how I make them is for me.