Golden challenge?? HELP!!

First of all, this is a great game. I love it! Im so addicted!!

However, I cannot, for the life of me, figure out what the golden challenge is, or how to beat it with three stars. I got up to level 146&150 with all three stars, but I cannot get the third or the bonus on these. Somebody, please help!!
Also, how do you get hints? I accidentally hit that button, and lost them all. :/ Now would be a great time to have them... Haha. -_-

Anybody, please help!!

Shelby Darden about Symbol Link - Game Challenges