You really should put your profile in your signature.
Anyway, if your 2011 is like my 2012, the PS is easy, just tighten the set screws that are under the plastic pop out covers.
The DS is tougher because you don't really "lock it down". You adjust the tension on a "friction spring" for lack of a better term. To access the tension adjustment, remove the lower trim cover ( mine also has the camera) and rotate the head so that the mirror faces the DS side window. In that position, you will see the tension screw and be able to tighten it.
2019 Phaeton 37BH