Maclaren Quest question - help, I'm useless!!

[Fluffyducklingsmummy]

I've just bought a 2nd hand Quest and can't figure out how to work the brakes. I'm not sure of the vintage of the puschair, it's grey checked and I'd guess it's at least a couple of years old.

There are little plastic "knobs" above the back wheels, but these don't seem to do anything if I try to manipulate them...

Help please!! Am I just being thick or are the brakes just dysfunctional....?

My Quest is same as Nahui's but the brakes are a bit rubbish tbh - seem to be especially bad if you travel on the bus so if you do keep hold of the handles at all times!

As Nahui describes, but mine are a bit rubbish too. Seems to be a bit of a design fault. So, you are NOT thick!