Everything is done via a set of coded hand signals and other gestures. Speaking is considered a breach of protocol so make sure you are prepared before you enter.
Get there a bit early. When you walk in, signal your intent to meet with someone imminently by thrusting your left arm straight up with two fingers extended, grabbing that arm by the elbow with your right hand, and waggling the left forearm like a pump handle until the bartender sees you.
When he or she does, they will pop themselves on the side of the head with an open palm to indicate that they have seen you and understand. This way you can sit at the bar, but they will know that your ticket may need to be relocated to a table soon, which is just a procedural pain for waitstaff sometimes unless they know in advance.
They will then look into the angled mirror above the door to the back and make a wing-flapping gesture. The coordinator in the back will then assign you a "floater" server by making the two-handed butterfly gesture into another mirror that is angled to reflect into a series of other angled mirrors mounted at various points along the upper walls around the place. That is to say, they're not actually assigning you a specific server yet, they are just alerting the service staff that one of them will soon have guests in their section and will need to claim the open floater ticket to keep with their section's stuff. The servers keep an eye on these mirrors every few seconds and once they see the butterfly gesture, they'll high-thumb their nose to acknowledge. But you don't really need to know those signals because they are internal to the staff team.
When you have sat yourself at the bar, place one finger behind your ear and push it forward a bit, indicating that you wish to know what the specials are, if any. If the bartender smacks their elbow, there are no specials right now. Otherwise they will point at the specials board and relay they prices of each item via finger counts, which you should be able to work out just fine, unless it's two-for-one or something, which can sometimes be confusing. But if you are confused, just make a gesture like you're wiping off a fogged up window and then use your index fingers pointing at each other and make an offset rolling motion with each to indicate a restart.
If you want to go ahead and order something, point at your extended tongue. The bartender will put their fists on their hips to indicate that you should proceed. Use your elbow to point at the thing that you want, a sample of each (or icon/sign) which will be arrayed on a sample shelf behind the bar (which you need to memorize for later). If the bartender does a single chicken-wing-flap with an arm, it means they need you to indicate which size of that particular thing you want. If you want a smaller one, place your forehead on the bar briefly. If you want a larger one, place one fist on top of your head.
When your date arrives, stand and greet her and do the hellos and whatnot and then find a table. The server coordinator will put out a bar-wide alert gesture in the mirror network and the servers will know that the floaters have picked a particular server's section. That server will soon notice and raise one hand out in front of their face, palm inward, and will come over to take your date's drink order.
Your date may wish to order for herself, so if she begins to gesture or flap, just leave her to it. Otherwise stand and face the server with about two feet of space between you and order for your date. If you want to order her the same thing you've got, place two fingers over your mouth like the shush gesture but also the peace sign. Otherwise tap your left shoulder with your right palm however many times you need to to indicate the numeric position of the item from the sample shelf that you memorized earlier. Indicate any necessary size designations and then cover your eyes with your hands to indicate that you've completed the order. The server will raise a knee and spike their elbow down onto it to confirm.
Watch the other patrons and staff to pick up any other signals that might be unique to that bar, but the above is really all you need to know to get started at most places. You'll get the hang of it pretty quickly. Good luck with the girl!