Open your OsCommerce shop on the server and open the OsCommerce package you received.
What you have to do:
1. Copy all the files from the root folder (excluding folders).
2. Copy /images folder
3. Open /includes folder and copy header.php, footer.php, column_left.php and column_right.php files
4. Copy /includes/boxes folder
5. Open /includes/classes folder and copy boxes.php file
6. Open /languages/english folder and copy /images folder
6. Open /languages/espanol folder and copy /images folder
6. Open /languages/german folder and copy /images folder
7. Open /includes/modules folder and copy product_listing.php and new_products.php files
That's all! Let's check the results...