You own a Bronze week. Either you reserve week 50 in your unit -- any time between one year and six months in advance of your December week, or you "cash your week in" and get 1300 points to spend in the Hyatt or Interval system. At six months, your unit is "cashed in" whether you like it or not.
If you choose points, you can drop them into Interval, where they are good for two years. If you want to stay in a Hyatt, you may chose any week at any unit -- as long as the total cost is less than 1300 points.
What does 1300 points get? Sadly, the answer is "depends." If you trade down in size or season, you get more time. If you want to trade up, you get less time.
I typically got two weeks each year by trading down to one bedrooms and studios.