As outlined in #13 by kaho, this is already a good start for the planning. The door is set a bit further to the left. The shower fitting should come from the right side of the plan, with a channel placed there. Normally, I would leave it open and in case of emergency (showering!) use a shower curtain. Just kidding
Even better: use a double folding glass door from the top of the plan all the way to the bottom. So, two parts coming from above AND two parts coming from below. When not in use, you can fold them against the wall at the top and bottom, and when in use, you have a comparatively spacious shower of about 75-80 x 140 cm. I am thinking of something like this
The trick is that the shower fitting must not be in the way when folded away, therefore definitely on the right side of the plan!