This particular kaiten sushi store near us is called Sushiro. You'll see those kanji characters 回転寿司 on the sign post!
Nigiri sushi is the traditional style, with a piece of seafood placed over hand-rolled rice.
Maki sushi is roll sushi, but don't expect any "California Rolls" or "Dragon Rolls" in these establishments--the rolls here are traditionally kept to simple fish or veggies rolled into rice and seaweed.
The Gunkan sushi (literally, "Military Ship") are named after aircraft carriers - with the concept being a vessel of rice with some sort of topping on the "deck." Typically, gunkan sushi is topped with tuna, sea urchin, crab, roe, or a mashup of some seafood with mayonnaise.
Ordering at this particular restaurant is done via a touch screen display - if the store has a touch screen, they'll usually have multiple languages available to select from (this store had Japanese, English, Chinese and Korean). We used the Japanese option, since my husband can read it confidently, but if I was by myself I would have used the English option! Some other kaiten sushi outlets will either have a piece of paper where you manually write your order, or a chef will be behind the counter to take special orders. The universal option for kaiten sushi places is just to take what you want from the conveyor belt.
You might notice that on this dish that my husband is about to grab, there's a white label on the bottom - which corresponds to the white background on our table number (21). You can also see in the picture there are other tables with different colors - red for table 11, and yellow for table 12, for instance. When the food you've ordered comes your way, the screen by your table plays a chime sound, and then it's just a matter of grabbing the plate that corresponds to your table color.
They will scan this barcoded slip, which you take to the front counter so that the staff member knows exactly how much you're required to pay.
And that's it! We had a bunch of plates as well as some udon and french fries (eating out with a toddler means that is a bit of a necessity!) and all up it was only 1220 yen! There is higher end stuff, but most dishes that we had on this occasion are 100 yen. The standard range for a kaiten sushi in Japan is usually between 100-500 yen per plate.