In most restaurants, you can choose from one of the "Menus" or choose "A la Carte" dishes if you don't like the dishes on the menu.
A typical example:
https://maps.app.goo.gl/rXsNZwNM1swy1b3o7
The left side is "A la Carte" with a price for each dish.
The right side is a €22 menu including a starter, a main course, and a dessert, to be chosen from the list.
In most cases, you don't order the dessert at the same time as the other dishes. There may be exceptions, especially when a dessert requires time to be prepared, so you must order it in advance. The waiter will let you know anyway.
In a brasserie-style restaurant, you can order only one dish, whether it's a starter, a main course, a salad, or whatever.
In fine dining restaurants with renowned chefs (like the one mentioned above by John), you may not have to order anything , they'll just ask if you have any specific allergies.
The chef is in charge; you don't choose your dishes.
An example from a restaurant I recently ate at:
A single menu for €89 with no description of the dishes and a choice between 3 or 5 glasses of wine that the sommelier selects for you, the meal consists of 14 courses and lasts about 3.5 hours.
https://maps.app.goo.gl/GBwPFdrsbVQu66ZE7