During all the stages of design I suggest you get involved as much as possible and understand that meetings are important, not to just you but also for the designer.
Its important for the designer to capture the design as you want it so explaining the design in more detail would be appreciated.
Not everyone thinks the same
If you leave the design up to the designer you many not necessary get what you expected. Its important to remember that everyone thinks differently and there are more than one way to do something. If in this case you are not happy with what the designer has come up with then you may find yourself forking out some more money to change the design.
I suggest a minimum of 3 meetings to review the design. Nowadays designers can email pictures of what they have designed so its not even necessary for you to be in the same room as the designer to have a meeting.
Minutes of Meeting
Its a good idea for someone to take a minutes of meeting. This is basically a list of all topics discussed during any meeting you have with the designer to stop any issues that may arise at a later date.