Briggs seems to be one of the larger nurseries around. You can walk for quite a while and still not cover all they offer.
Because of the size, it's not a good idea to wander and hope an employee will find you and ask if you need any help.
The employees make themselves findable by being at the front of the facility, and it's up to you to decide when you'd like some outside help.
My wife and I would take notes / questions and then go to an employee to get them all answered at once.
The great selection really helps give you ideas, and the staff can fill in any blanks with suggestions.