Fitting 1/4 landing

[redrob]

Hi all,
I am looking for some detailed advice on fitting a 1/4 landing. due to adding an extension we have to change our staircase to T shape this is supplied with a bottom section 9 risers to a 1/4 landing (not supplied) then 2 risers left and right after this. There is a solid block wall to the left and a stud wall to the rear of the 1/4 landing position. What is the correct process for fitting the landing to support the stairs etc.

Many thanks