Not sure you need curtains there. But if you want to add, I would put a track on the ceiling and mount full width curtains for the whole width of the wall in white.

Window treatments serve three purposes: light control, privacy, and aesthetics. Do you need light or privacy control? If yes, then perhaps some sort of shades mounted on each door/window would work. Fabric Roman shades, natural wood/bamboo, etc. It is going to be difficult to install curtains on the wall because there isn't a lot of room for them to "stack back" on the sides when open. Even if you mount the hardware on the ceiling, as modpod suggested, you have to consider the stack back. I'd do shades.

I don't know the reason for you wanting drapes (functional or aesthetic), but I don't think they work here.

1) With the step on the left, the panel would have to be at the elevation of the exterior and matching that on the right would make the panel feel odd.

2) Very little space on the left

Do the doors open in?

Given the door and need for outside accessibility, don’t think you can have drapes on the left. They could rest on right and pulled across; picture below may help visually.

If you want/need privacy, I‘d treat each side separately with some type of blind.

It looks as if putting curtains on the door on the left might be a little difficult. However you might be able do something like in our living room design in the second photo.

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