I take mine to the digital output company as suggested. They will give you choices of what they can mount it on, and they might be slightly different in cost depending on what you pick. Also they will give you the option of trimming or not. Remember that some of their substrates might be tricky to trim like Mighty or Gator. Best to let them trim that. Do you have a vehicle to transport it back to the shop? They probably offer delivery if you don't. They also might want to charge you tax, so you might have your resale certificate handy. They always say that now and then, it could get messed up, but that has not happened to me yet. Also give 'em a few cards, as they probably work with archititects, engineers, graphic designers....
Susan