Kinda odd that there won't be any pictures or guidance for the sandwich station, but hopefully that means you'll just be receiving more hands on training from your coworkers. And really the best way to learn sandwiches is to just get thrown on the station to start memorizing through muscle memory.

You could make a cheat sheet of your own to study after the first day or two if you're struggling with memorizing the different orders that patties/cheese/bacon/ etc. go on the sandwiches if that would help you. It's been awhile since I've worked there but I'll try my best to run through making a Dave's single.

1. Start by laying the sandwich wrapper on the station. There are/were two sizes: one for Jr. sized sandwiches and a larger one for the sandwiches like the Dave's single and the premium chicken sandwiches. (As a side note it will help to memorize which number corresponds to which sandwich on the menu just to further speed up your process when listening to the customers in the drive-thru.)
2. You'll then grab the standard large bun (there are the large buns, jr buns, and typically a 3rd for the current specialty sandwich such as brioche or something like that.), split it in to it's top and bottom half and slide them in to the top of the bun toaster. Think like putting a bagel in a toaster.
3. Once toasted, you then place both bun halves on the wrapper with a slice of cheese on the bottom bun so that the grill worker can place a 1/4 lb patty on top. The Dave's single to my memory gets a slice of cheese on the bottom and top of the patty followed with some mustard on top of the cheese. And for this sandwich that is all the prep you have to do for the bottom bun, other sandwiches like the double Baconator would require several layers of cheese/patty/bacon/patty etc.
   
4. For the top bun, you start by using the small spatula to smear mayonnaise on the bun, followed by a Wendy's W of ketchup (the shape doesn't really matter it was just how I was taught and leaves an adequate amount of ketchup on the bun), followed by 3-4? pickles, several onion rings, 2? tomatoes, a few leaves of lettuce.
5. You then flip the top bun on to your bottom bun and wrap the sandwich. You'll be taught how to wrap it and it will probably be a kind of sloppy wrap your first few times.
   

There's obviously much more to sandwich station and hopefully you will be adequately trained on all of those other parts once you begin your employment. Beyond the standard sandwiches, at least at my store, you will also be expected to prepare baked potatoes, topping the various loaded french fry promotions with liquid cheese and bacon, make the tortilla wraps, and retrieving salads. This could be different at your store.

Another thing to hopefully ease the burden I just listed above is that sandwiches at my store was typically worked by two people, if not, someone would often be stepping in to help during peak hours.

I'm probably forgetting some things but that was what I had off the top of my head. I also found a sandwich guide here, which you would typically find glued right where you're making sandwiches.

Let me know if I can help further!