Multiuser use website?

Question

hi,

for ex : i want ->Am a employeer i want to save my employees document to my login pages so

First to register the form after getting one username and password doing the above task .

second go to save my employees details.for ex : uploadfile.aspx this work is done .

 

Now My  problem is my website to use multi User employeers.How to do this same process for using all employeers.

 

can any one explain or send refer link or send mail [email protected]