I worked as a seater back when it was called Full Service Food and Beverage. That role encompasses 5 different jobs within the restaurant: Seater, Greeter, Assigner, General Teller, and Setter. Full and part time hostesses have scheduling priority, so they get first choice for Assigner and GT. Some restaurants don't even let CPs work in those roles.
So for the most part you'll be Seating, Greeting, or Setting. Seating is fairly self-explanatory. Once a party is assigned to a table, you'll grab menus and take them to their table. Seaters are also usually in charge of prep work like rolling silverware or folding napkins. Sometimes I folded napkins straight for several hours.
Greeters work at the front podium, using the computer to check guests in. It's pretty simple once you get the hang of it, but the better you know the restaurant the more effective you'll be.
Setters are in the dining room helping clear and set tables. At some restaurants this is a scheduled position, while in others you just help out as necessary.
The assigner is in the dining room with a tablet assigning parties to tables. It's a harder job because you have to really understand the restaurant's flow so you don't overwhelm the server or the kitchen. This also can involve some clearing and setting of tables, depending on the restaurant.
The General Teller is in charge of the restaurant's cash. In the restaurants I worked in, you really only use the cash at the end of the evening when you bank out the servers. You work as a seater for most of the shift.
Your schedule and what you do every day depends on the restaurant and the role you're scheduled in. I worked in a restaurant that was only open for dinner, so my shifts were usually only around 6.5 hours long. For most of my program, I worked as a Seater 4 days a week and a Greeter 1 day a week. It was only during my last few months that I started Greeting 4 days a week and being GT once a week.
Depending on your restaurant, you might be insanely busy or have a lot of down time. I worked at a Signature restaurant in a resort, so we had a lot of quiet evenings. However, if you work in a park you're much more likely to be busy all the time.
If you have any more specific questions, feel free to ask!