Note that this hotel is listed as 3 stars on booking websites and it's in a small city, so it may be different in more expensive ryokan and/or in larger cities.
A typical room
When you enter the ryokan, you may be expected to take off your shoes and leave them at the front. Leaving your shoes out in front of the lobby might feel a bit odd, but that is how some operate. You'll get a pair of slippers to wear inside the ryokan; when you're heading out, just place them on the shoe rack and put your own shoes back on. If you're having meals at the ryokan, they'll ask what time you want to have breakfast and/or dinner before taking you to your room. Some ryokans may let you wear your shoes into the ryokan, but you must take them off once you get to your room, as tatami flooring is not meant to be stepped on with shoes.
A Japanese-style room will have a little entryway where you take off your slippers (or shoes), before the flooring becomes tatami. The room is usually fairly small, as the space can be used as both a living room and bedroom. During the day, a low table will be set up along with cushions or floor seats; in the late afternoon/early evening, staff will come to set the table and seats aside, and set up futons and blankets for you to sleep on. Then, if you've got a window or balcony, there's usually a little sitting area with chairs and a small table so you can sit and look outside. If you've never slept on a futon before, it may not be the best idea to book a long stay at a ryokan, only for you to develop back pains.
On bathrooms: Unlike western hotels, not all ryokan rooms have private bathrooms. This might not be a concern for some, but if you're used to Western-style hotels, this might be something to think about: are you willing to use a communal bathroom? Some ryokan do offer rooms with bathrooms, but you can expect to pay more for these rooms, and the bathroom also may not be what you expect. In Japan, the toilet is often in a separate room from the shower/bath/sink area, and toilet room tends to be about the size of a stall you'd find in a mall bathroom. Some rooms may also feature a toilet room but not its own bath, instead offering a shared bath.
Most ryokans offer meals: breakfast or dinner or both. As a lover of Japanese food, this is easily my favourite part of staying at a ryokan. Many western hotels do buffet breakfasts - which are nice in their own way, don't get me wrong; I love getting second (and third) helpings of salad in the morning - but I loved the breakfasts at ryokan: a large tray with a variety of delicious foods, including warmed soft tofu, omelette, rice, several tiny side dishes, and a small bowl of soup. During this stay we opted for half-board, mostly because we didn't know if there were going to be any restaurants nearby, and we didn't know what to expect. My expectations were blown out of the water by the quality of the food. I still think about those dinners, months later. I'm pretty sure I could write poetry about them. The amount of food was also very generous.
Note that at many ryokans, you don't get a menu to choose from: the chef decides the day's menus, usually based on what's in season. The offerings will usually include rice, a simmered dish, a boiled dish, a grilled dish, sashimi, tempura, soup, and pickles, meant to highlight the local area's specialties. Some larger ryokans may offer you choices, but smaller ones may not: checking their site will usually tell you which one is the case. On one hand, this may be a great opportunity to try something you normally wouldn't pick for yourself; but it may also pose a potential problem for those on specific diets or have food allergies. If you have any special dietary needs and/or allergies and your ryokan of choice is the type that doesn't give you choices at mealtime, it's probably best to check if they can accommodate before you book a room with them. If you don't like sashimi, you might want to ask about that as well, since most dinners will include some kind of sashimi.
I'm quite fortunate to not have any food allergies or a particular diet, so my only concern was the lack of coffee at breakfast. Thankfully, coffee is easy to find in Japan.
At some ryokans, especially larger ones that are more like western-style hotels but with Japanese-style rooms, you may have the choice to eat in one of the in-house restaurants which could be a la carte or buffet style, or you can order a meal like this one to eat in a private room. At smaller, more traditional ones that don't have their own restaurant space, meals will likely be served in your room or in a private dining room.
What else to consider when considering a ryokan
A possible language barrier. Especially if you're heading somewhere that doesn't see many foreign tourists, the ryokan's staff may not speak much English, even if they can be booked through sites like Expedia and Booking.com. Even some larger ryokans may only have a few staff that speak English if the majority of their guests are Japanese. But they are prepared to do their best to serve you even with a language barrier, and a little patience will go a long way: especially if you have a dictionary or translation app on hand.
Paying for your stay. Not all ryokans (especially older ones in smaller towns) accept credit cards. Some may allow you to book online and pay in advance with credit card but will only accept cash if you choose to pay at the end of your stay; so check before booking! We chose to pay in advance, and at the end of our stay we just had to pay for the alcohol we drank at dinner, which we paid in cash.
To sum up, staying at a ryokan is a different experience than staying at a hotel. It's meant to be a little more personal than a hotel, where the staff will try to get to know your preferences and needs and meet them even in the little things. There are some that are more like inns and others that are more like luxury hotels, and you can usually tell where a ryokan is on that scale based on the price for the rooms; but that also means there are ryokans for a range of budgets. I definitely think it's definitely an experience worth trying at least once! If you're worried about it not working out, the safest bet may be to book a well-rated ryokan for a short stay to test out if you like sleeping on futons and having your dinner decided for you. I hope this article is informative and gives you some ideas as to what to consider and plan for if you decide to try out a stay at a ryokan!