We installed this shower door ourselves. I read the instructions very carefully, several times,  to make sure I understand it. Overall, good instructions and very high quality parts. Called their support line to ask about the drill bit size for the anchors and they said to use 1/4" for both rail and bottom brackets. 
 The main problem I ran into was that the wall anchors don't fit into a 1/4" hole. Eventually, I purchased smaller anchors that fit a 1/4" drill bit, and also longer screws to make sure I get to the studs. 
It took most of a day to install and required at least 2 people as the doors are very heavy (ours are 60-64").
The effort is absolutely worth it as the bathroom looks gorgeous. The look is very high end and the door slides extremely well - quiet and easy to move,  yet also stays in place. Highly recommended!