Boxing in advice needed

[iankuk]

Heya, I'm new here and looking for some advice please.

We've had a new shower tray installed and I'm advised that I need to box in this area, leading up to the ceiling.

I'd like to know what I should be doing here, long peices of wood, screwed into the wall and then panels installed over it?

Constructive advice for this newbie appreciated.

 

[iankuk]

A bathtub has been removed and are installing this showertray instead.

I need to know also:
What to use to fill in the hole/line where the bath was.
What to do with the walls if we don't wish to use tiles.

Again, please forgive any lack of knowledge on my part.

 

[Jurassicspark]

To box up that area (the first image) get a piece of timber and drill to wall, (cut in three pieces) then some MDF would be okay.
The second one would do with some cement.

What to do with the walls?
You can get it skimmed and painted over but tiling it would be a better option IMO.

 

[^woody^]

Lol. I would not class that as "installed".

You are better off using Hardie backer board or similar cement board, fitted to a timber frame screwed to the wall.