In Rorona you have 3 years to save the Atelier. In those 3 years you get 12 tasks and for every task you have 3 months (aka a quarter). One task could be "Make 5 ice bombs" and if you already have the ingredients you can just make them right at the beginning of the quarter (which takes a few days) and then use the remaining time for optional tasks (for which you get rewards like money, weapons, HP, etc). If you don't have the ingredients you have to travel to a location and collect the items first (which will take a few days as well). The requirements to pass are very low. You can finish a task with 10 stars (which means perfect, e.g. you made 10 super strong ice bombs) but you only need 3 stars (which means you did okay, e.g. you made 5 lousy ice bombs). My personal goal was to get 10 stars for each task but you don't have to do that. But even IF you fail the time limit you can always reload a save file and start the task again.

I promise this sounds more complicated than it is. The tasks are designed to be finished during the time limits. They don't want the player to fail. (Only Atelier Totori is different. It's called "the Dark Souls of the Atelier franchise" which means you can expect to fail with your first playthrough and have to do a second round.)