hi I want to make a
cloud server allowing:-
clients to write to open office files by going to web browser.
users have read and write permissions.

all the files should be stored on server.
Any tutorial on this subject.
thanks for help in advance.

Hmm, typing "how to setup a cloud server" returns over 17 million hits. Here is just one. Google is amazing

thanks for help.
but i want to make a solution by using lamp server and starting from source.
any tutorials ?

Many...again, have you tried Google??? What you're describing seems like you want to set up WebDAV. But why would you re-invent the wheel, when there are MANY already available solutions?

I wannt to sharpen my skills as a developer.
I was thinking to make website (local) to 20 computers:
clients (20 computer) are file editors (using windows infected viruses)
so in oreder to protect files a linux samba server is setup to share files with windows.
so I was thinking cloud website may help.
but don,t know where to start what topics i should search ?
thanks for help again.

Why would you think that?? A cloud is a storage medium...a virus on a file there is still a virus on a file. Unless you clean it you're not accomplishing anything.
Did you miss the part where you were told about WebDAV? Did you look at any of the other sites that jkirchner said you could find through Google?? And if you want to sharpen your skills as a developer, then by installing LAMP, you'll have the TOOLS to build something. Build whatever site you'd like, with whatever features you like. If you want to edit files through a web browser, a search on Google or Hotscripts will show you lots.

Thanks for help.