When using the Runner, just keep going left until you have done one full turn. By this time, you will be at the end, and can finish the level. When using the Skater, just keep going pretty straight until you finish. This level is harder than most at this point, but do this and you can finish it easily.
For first time players, the Runner is recommended, since she is slower and easier to turn right/left, and her jump height can let her change gravity in midair, so she can land on another platform easily.
The Skater is also recommended for skilled players since he can jump really far away, so he can land on another platform far away, which is rather big for a level so short.