Best to get a manual for it that explains the procedure. Jen Sales is one company that has them. It's not complicated, but the manual spells it out well.
There's adjustment screws underneath the rear end.
And you adjust them by measuring the amount of brake free-pedal. I don't recall the dimension they stated.
I had a 5040, but the manuals went with it; otherwise I'd scan a page or 2 for you.