This is what I first used but I found it frustrating but it might be easier to understand. Create some random timeline and name it whatever you want (tl_miku01 or tlMiku01, whatever) and then create some object (for the sake of it will be obj_miku) and in the creation event of the object and do something like this:
What this does is it will run the timeline in order per frame.
In the timeline you can click the button with a big green + sign called Add. This prompts a menu to select a moment in the timeline to add something to it.
0 = first step in the timeline
500 = 500th step in the timeline (or 500/50 seconds after the timeline starts)