I don't know if I already said this but I know in the original series Al would adjust the image to make him appear to rise up and walk on water or something.
So if she was sitting on the shuttle she was probably just sitting on the floor.
I don't know how the stands might have been addressed
She was clearly SITTING on the edge of the shuttle bay (someone sitting on the floor looks rather different). It wasn't just an "adjustment," of the kind that, yes, Al used to do all the time to account for the realities of filming without using the green screen for every little thing.
I mean, sure, if we NEED to find an in-world explanation, we can posit that she brought a chair in, and coordinated the image orientation JUST perfectly, but let's face it, that was never stated in-context, and was laziness on the part of the director. (I honestly think the director just assumed "she's a hologram, so we don't need to give her a space suit" and failed to consider that it also meant she couldn't sit on the surroundings)