A warning, first of all -- do not place this venue in your dynasty file (Immortal, Townie, or Life state) until permission is given. Your household automatically gets the revenue from the restaurant. You don't have to buy it.
My apologies to anyone who read the above. You won't own the venue if you place it in your town. If you want to own the venue, you have to own the land that it sits on, and you have to buy that land and make it a community lot before you place the venue or the oven and menus. Once you have placed them, you should then have your sim visit the lot in order to hire a chef, set up a menu, etc.
Another warning or perhaps advisory -- it appears that townies in store worlds won't come and use it. I had plenty of townies come to eat there in Starlight Shores, none in Aurora Skies. If you're not satisfied with the number of customers, have your sim invite out some friends.
Children cannot eat in the venue. They can't use the menus, and if you cancel the parent's eating action, the plate of food disappears and is replaced by the menu.
The good news is that you can offer whatever dishes are available to you. If you have the wood oven from Monte Vista, those dishes appear; ditto for the ones from WA and LN.
Other good news is that if you place a Late Night bar in the venue, a mixologist will come. I don't know whether your sim will collect revenue from it, however.
My impression is that the higher the level of the chef, the longer they'll stay at work. A line cook seems to work a very short shift -- about 2 hours; a sous-chef stays longer. The chef's level might also influence what you can have on the menu. I don't think you can offer lobster thermidor with only a line cook.
If you put the oven in your house, you can have a chef come and prepare your meals. Unlike the butler, the chef serves only what you order -- all the chopping that he does is just for show.
I haven't experimented with putting the oven on other community lots. If you do, you need to also place menus on the tables. They're found under Appliances and cost 5 Simoleons.
I also haven't experimented with using the venue for a date.
I hope we will be able to use the oven and menus on the properties we already own in the dynasty files. I doubt we'll get that much revenue from them, especially in the store worlds, and the experience of dining out is definitely more fun.
Edited to add: I haven't figured out how to own the EA-designed venue. I'm not sure you can. I've tried changing the Community Lot -- Visitors Allowed designation to Community Lot -- Small Park, but don't get the option to buy it when I click on it.