When I came to job site I found that a wall that was going around the stairway was cut back.
The original wall was floor to ceiling.

The treads were sitting on 2×4 frame work, the place was a mess.
I was hired to curve new drywall along the stairway.

I had to add 2x4s and use three layers of 1/4″ thick drywall AKA sheet rock.
The sheets had to get wet for bending, then installed with screws.

Baseboard and trim was soaked with water, bent, cut to fit and installed.
The wet wood tend to shrink as it drys, so I cut it extra long.

I had to finish the ends of the oak treads with “nosing” trim.

Painting and tile work was done later.