[Pokered] Subanimation and frame-block questions

[CecilleTheMoon]

Hello!

I am making a ROM hack of Pokemon Red/Blue and I am currently working on adding new moves into the game.
For one of the moves I have added, X-Scissor, I am having a few issues getting its animation to look cool.

I am trying to mirror of the Subanim_0Slice used in moves like Cut so that I can draw a X shaped slice animation, but I haven't been able to do so.
There are a few things I don't quite understand about BaseCoords and Frameblocks.

I need some help understanding what each bit in the frameblock data is used for.
For example, FRAMEBLOCK_2A used in the slice subanimation has the following data:
FrameBlock2a:
db 4 ; #
dbsprite 0, 0, 0, 0, $44, 0
dbsprite 1, 0, 0, 0, $44, OAM_HFLIP
dbsprite 0, 1, 0, 0, $44, OAM_VFLIP
dbsprite 1, 1, 0, 0, $44, OAM_HFLIP | OAM_VFLIP

I am not sure what these bits are referring to, any help understanding this?

I am also not certain on how to read the BaseCoords data, as it seems that the coordinates of where the sprites in the animation are drawn are already defined in the frameblock.

Please help me, I am so lost!