I just finished my test cake. I'm making one for a birthday party this weekend.

It's the first time I've stacked a cake and the first time I've played with fondant. I have bubbles in the fondant, like underneath of it. How do I get rid of those?

I would use a tiny pin or needle and poke small holes in some of the bubbles, then try and run your hand along the other bubbles and see if you can get the air out of the other holes, without poking a million holes all over the cake. lol