@drivex1
Pls let me say afront that, working on brakes is a serious safety matter. You have to know what you do.
Scooters and motorcycles of later model years, let's say last fifty years do NOT have a common or shared brake fluid reservoir. For good reason. If the fluid would dissapear from an shared container for whatever cause, you would be all of a sudden without brakes out on the road. With known result. So two independent circuits are a MUST.
Concerning documentation and manuals: l personally rely on information from proven sources like this forum and riders who drove motorcycles and scooters for ages, own experience and sometimes l ask a workshop for certain data. But if you really want real-life info, ask here in this forum and you will be helped.