Creating layer of one buliding

[PeterFalkow]

Hi!
I'm new, and I have a task to create a map, with measurment points for wifi connection in building with three floors. I can't find any tutorial how to create a building layer. Can someone introduce me how to create my own layer, where every one who opens a web app with my map I can put on a point with some infos (some text and picture url) but no one, only owner of map can edit this points? This is very important for me to create such application.
Thanks for help in advantage!

[PeterFalkow]

Sorry for writing post after post but I think I didn't told what I need clearly.
I want to create map of building (4 floors - if I understand properely 4 layers, right?), where I user can put point with some infos and it become uneditable (if it is possible, but not necessary).

I have a very short period of time to do this but I have no idea how to start. Building dimension are 100meters x 25meters.

If there is someone who can tell me how to start working with on it - please write me as fast as you can. It is my passing project on university but the biggest problem is that I didn't have any class about working with GIS.