As you enhance your facilities by completing tasks, you'll earn points that can be exchanged for a variety of rewards, including tokens, boosters, in-game currency, or special fragments.
Even if you can't unlock the new attractions immediately, don't worry! The fragments you collect will accumulate for future events, allowing you to unlock them eventually. Once unlocked, you can continue to collect fragments in subsequent events to level up your attractions!
Check how the rewards menu works: