The points from Eustacio: You need to participate in 3 raids which you can check with him saying "hi - location". First raid is the Spyrat attack, near the coast of a city Spyrats will appear on water and you need to use the Orb to make your path to the Spyrats, Each Spyrat you kill gives you 5 points. The raid ends when 60 Spyrats are killed. Next one is the Pirat Invasion, in which Pirats will invade the city and you need to kill them. Each Pirat you kill gives you 3 points. The raid ends when 100 Pirats are killed. Third one is the Ship Invasion, Pirat'ships will invade the coast and you need to shot with a catapult to the ships run away. To shot the catapult you need to use a pick on the stones nearby to get a Ballistic Boulders and use them on the Catapult, then you use the Flintstone to light the fire and use the catapult's lever to shot. You earn 2 points for each step (6 points for each shot). The raid ends when 50 shots are fired.
Once you complete 1500 points you talk to Eustacio and gain access to the island, then you don't need to make these points again.
The points from Tik'hi Tak'he: You need to complete the island's events, which is the Memory Test, The Journey, The Stealth Mission and The Supply Mission. When you complete The Journey, The Stealth MIssion and The Supply Mission you earn 200 points and can repete the event after 20 hours. The Memory Test can be repeted each 2 hours and you can earn maximum 50 points (5 for each pattern you get right). After you compelte 1200 points, you use them to access the final boss. You can keep doing these events to get the new decoration items from Tik'hi Tak'he and also the new backpack.