The book says between 3-5 kg force on the plunger, then screw in the adjust nuts until it rests on the plunger. Once it touches, back it off by about 1/2 a turn and then your done.
Or if this is too complicated for you and your chain is rattling. Carefully tension the adjusting nut with the engine running and keep going till the noise stops....then about antoher turn. First option is best though...