Easy, Your penguin has to be 45 days old or older, (You can check on the bottom right of your chat bar). Go down to the ski village and click on the booth that says 'TOURS'. A poster will pop up then at the very bottom it will say,
"Would you like to become a tour guide yourself? Click here for more details!". Click on it. You will have to do a test that is REALLY EASY. then if you pass it, click on your penguin, go to your head items, and click on the tour guid hat! When you get it just 'Wave' and the sign will pop up.