I've been to several in the N. Va area.
Most ranges will rent earmuffs and safety glasses which are mandatory, but often the glasses are very scratched up. You probably want to buy your own, usually about $10 each.
Get a gun bag. WalMart has decent ones. Put your unloaded gun(s) in there along with your targets. Most people agree that cheap paper plates with some red sticky dots or Shoot-n-See's work great...again, available at WalMart.
So you and your girlfriend will walk in and you ask the guy behind the counter for some range time. Depending on the time of day, that may be just an hour or indefinite. Some ranges require you to take an 'open book' safety test, and one even made me watch a really bad video for 20 minutes along with the test.
The entrance to the range usually has double doors. Let one close first before you open the other. Make sure your muffs and glasses are on.
Say you're assigned to 'lane 12'. Put your bag on the counter behind you or on the floor. With the gun POINTING DOWNRANGE, place it on the table in the booth, action open, unloaded. The carrier may/may not have cardboard, so staple your target to this. Don't feel bad if a range officer 'corrects' you from time to time...it's normal. Read all the range rules first before you take the guns out BTW.
You'll have a lot of guys with BIG hand cannons firing all around you. It'll jangle your nerves at first so don't worry. Sound really echoes indoors.
In the booth there should be a control box to send the carrier downrange. I'd start off with 7 yards at first to get a feel for where your shots will go. Remember...always POINT THE GUN DOWNRANGE when loaded. When you put it back in the bag, point it straight up with the action open.
There's more, but that'll get you started.