If you need to create a new product similar to some product already existing in your store, use the 'clone' feature. It allows you to automatically create a copy of a product in the database (a new product with all the options of the initial product) - which can be modified and saved as a new product. To create a 'clone' product:
Click on Search for products in the Products menu. X-Cart 'Product Management' section will be opened.
Use the provided 'Search for products' form to find the product you would like to clone. The products found by your search query will be listed in the 'Search results' form.
Picture 1: Search results.

Select the check box next to the product you would like to clone and click on Clone product in the lower part of the 'Search results' form. The 'clone' product will be created and the 'Product details' form will be opened allowing you to edit the 'clone' product details.
Picture 2: Product details form.

Edit the details of the 'clone' product (change the thumbnail picture, the name, etc) and save the changes by clicking on Save at the bottom of the page. The product will be updated.