Building a half wall in a L shape around stair case ?

Use standard dimensional lumber (2x4, 2x6). You can always cut the fake wood floors with a circular saw. Fasten frame directly into subfloor and walls. Cover the frame with some material (sheetrock). Base molding can cover the edge of the floor cut earlier.

Hi! I hope this answers some of your questions:

https://www.bobvila.com/articles/pony-walls/

Here is a good project.

https://www.hometalk.com/diy/build/walls/half-wall-at-top-of-staircase-32846117

Here's one using free pallet wood

https://www.hometalk.com/diy/90-pallet-half-wall-7404834

This may help: https://www.diynetwork.com/how-to/rooms-and-spaces/walls-and-ceilings/how-to-build-a-half-wall

not sure if this is what you mean https://www.google.com/search?client=firefox-b-1-d&q=building+a+wall+around+stair+case

Hi JB

Here is a video that may help you

https://www.youtube.com/watch?v=sWgccIjNdcM

Anchor it in the wall only let it float on the floor you could glue it to the floor