Please help with shower drain move / vent

Hi all, I had to replace one of the original walls that the prior owner installed it was all rotted out.

I need help with the drain please. I marked where the original owner ran the drain line under the slab. I had called a plumber in a few weeks ago who advised he would run a vent on the shower drain which he said should have been there all along.... as well as reposition the drain where X marks the spot.

My question is, does anyone know the likely layout based on my picture for (1) the new drain line and (2) the new shower drain vent? I need to frame the last wall and do not want to yet until I figure out whats going on with the drain and vent.

Thanks in advance !

1- for us to make any type of ;informed statement, we would need to kno2w dimensions and the location of the existing waste stack the shower is tied to (if any)...
It would be helpful (from the plumbers' point of view) not to have the vent wall framed as he is going to have to bust up the floor there to run the vent...
Have him come in aand do the "underground" then frame and he can come back and do the top out and then trim...

As well - look into the Kerdi system now - johnbridge tile forum is a great help in that...

Mark this is exactly the guidance I needed -- thank you.

I am planning on doing a Kerdi shower thanks for the direction there too. I bought John's books.

Best regards