On what files? You really need to provide a little more detail if you want people to try and help you.
when i upload all the files to my web server, before opening install.php do i need to set any file permissions?
No – not initially.
But later on, if you have any problems with file uploads via the WP dashboard, you might want to try changing the permissions on the wp-content directory to 766. If you still have upload problems, try 767 or 777. Once your uploads are working, change the permissions on wp-content back to 755 again and check that everything still works OK.