To do this task
In QuickBooks, go to the File menu and choose Open or Restore Company.
Click Open a company file and then click Next.
Browse to the location of the company file you want to open. If you can't find the company file,
see Finding a file on a computer running Windows.
Select the company file and click Open.
If QuickBooks asks you to log in to the file, use the user name and password assigned to you by the QuickBooks Administrator.
About multi-user access
Changing your password