|A sample sequence.|
A timeline differs from a sequence, because the duration of a timeline is the entire animated flipbook.
A sequence is a drawing of just one particular object, and how you want it to move or interact with other objects.
Concentrate most of your energy on composing sequences in anticipation of moments where objects interact. Get good at determining when those events will happen in your timeline (see next exercise), and you will have some very amazing flippers in your back pocket. And that's for real.
So go ahead, draw some sequences. Listen to some songs while you do it.