Help with bgctrl

[Slayer.]

So I'd like to use bgctrl for an element of a stage, but I couldn't figure out how to do it.
The concept of the movement would be as follows:

Part A:
- Begin Action 1. Stand still for 20 seconds.

Part B:
- Begin Action 2. Parabolic movement, distance between the start and end axis is -126 pixels, with movement of -19 pixels on the y axis. 1 second long.

Spoiler (click to show)

Part C:
- Begin Action 3. Stand still for 10 seconds on the new axis (post-travel).

Part D:
- Begin Action 4. Same movement as animation B, but with inverted horizontal direction (+126).

And then it loops.
Although it is possible to do this with just a begin action, just the first part of the animation using only 4 frames with 11 ticks each, would make a wall of text and would not have the natural movement.
Thanks in advance.

[Odb718]

It's been a long while since I messed with a stage. But what comes to mind is to make 3 or 4 different animations. All of them would be blank while the other one is playing.
So all 4 animations would be 32 seconds long.
A would play for 20 seconds then be blank for 12.
B would be blank for 20 then on for 1.
C is off for 21s then on for 10, then off for 1.
D is off for 31 then on for 1.