Rear Drum Brake Adjustment

Recently completed my first build and am having a great time. It is a Grubee chopper. It has what they call a drum brake on the rear and works minimally. It does have two adjustment screws, but since I can't see what I am adjusting inside the sealed housing I am reluctant to mess with it. Can anyone give me an idea where to start? Thanks

I'd check Grubee's web site to see if there is anything regarding making adjustments.
Since they sell that brake there could be some information in their site so the owner can
take care of his machine and enjoy it without endangering himself or anyone else. If not
use their contact info and explain your situation to them. I'm sure they would get back
with you regarding it. Something as important as that (especially on a product THEY sell)
should have some basic service info for it somewhere in the site. (that's just good judgement
on behalf of a business, plus any person browsing their site or any other site couldn't help
but to be reassured by that kind of commitment to little details)