[users] Q in OO calc 2.1

[Indra Gunawan]

I have 3 files such as  file1, file2 'n file3.  how to added the value of
file1 + file2 and the result in file3. Usually i use Link in excel and
everytime the value in one of file was changed. the result automatic
changed. 
 
how to implement in OO. anyone help me ?
 
 
thanks a lot