Hi,
I am not an expert but here is a simple rundown if you still need it.
1) Create your database on your site with mySQL (your hoster can help you with this).
2) Copy the"oscpm1_upload.php" file to your catalog folder (FTP)
3) Open a browser window at address
www.yoursite.com/catalog/oscpm1_upload.php You should get a green bar saying everything ok.
4) Open osCommerce Product Manager and put in your connection details ()the database username and password).
5) Then double click products to edit
Hope that helps.