In older radiators with plastic top/bottom covers the bleeding is on the left side of the radiator. It's an oblique plastic valve that has a hose connected. You have to turn it left to open with a 19mm wrench.
In full alluminium radiators the bleeder is a plastic screw in the front of the radiator, in the bottom. It's a 10mm allen screw.
In the online manual, the bleeder is described as "Connect/disconnect control". They only show the older plastic tank radiator and not the aluminum tank.