Installing wall mounted tv unit & mirror hanging

I have a large tv wall panel that needs to be secured to a wall. The unit is heavy and sits on a plinth that needs to be fixed to the wall and then the unit sits on it flush to the wall. The tv is then installed in the unit itself. I can assist with the lifting but I need someone more adept than I to do the main installation as it has to be done right. I have three large mirrors that have to be fixed to the wall. All must be at an equal height and with a fixed distance between them. They have defined fixing points on the back so they sit flush to the wall. Requires a level of precision that I clearly do not possess.