Do you mean where to put a pony wall? If so, put it along the back wall so from the toilet you face the wall rather than look into the shower.

If you put the shower head on the wall between the shower and the tub, the controls can go under the shower head or on the pony wall. If you put the shower head on the back wall, put the controls on the pony wall or on the wall between the shower and the tub so you don't have to step into the shower to turn on the water.

Thank you. Wonderful advice. One more thought for you. If input the shower head on back wall how would it be w no wall between shower and tub.

No wall could work too. My parents' master bathroom shower only has two walls and they like it just fine. The only thing you are going to have to figure out is the drain situation. Were you planning on having a curb or not? My parents shower floor is lower than the bathroom floor. I'm not sure the above picture would meet code as it appears not to have an acceptable slope from the shower entrance to the drain.