Each word spelled gives one Hairy to jump with. At the top of the screen it shows how many Hairies you need to save by jumping across. On level 2 you need to save 4 Hairies so need to spell at least 4 words before playing the game. The number of Haires you have to play with is shown on the igloo.
On level 2, double tap a Hairy to make it do an extra big jump. Multiple taps while the Hairy is in the air will make it go further.