How do you regulate brakes?
How do you mean regulate? The brake is operated on the handle as a hand brake, and, I hope I am not wrong, the same brake serves as a central brake after locking it with the extra mechanism to stay in place, braking the stroller. The handbrake for slowing down works pretty much the same way as on a bicycle, just having that locking option extra.
Here is the pdf manual of Emmaljunga NXT Challenge, if you needed that.