You can earn the bronze, silver and gold stars in career mode. The tutorial’s stars don’t count for these achievements. I got all 3 of them after going to 2nd option in the career menu (Captain Lockjaw) and selecting the “Pirate Battle” scenario.
Here, I just placed all of the rides and spammed some scenery near them (make sure you open the rides too) Then, I sped up the game (by holding
a few times). And then I waited for the money to come in and guests to be attracted to the park. Then I got the 3 stars. However, if you don’t get enough guests or money I recommend placing more rides and getting the park rating up (see this in the park management menu by pressing