What do I do don't have a product code for the 3D program ?

Did you get the "dongle" with the software? It looks like a dark red USB stick and needs to be inserted before you can use the software. However, you also need the code to enter when you are installing the software. If the software came in its box, there should have been a piece of paper in there with the code on it. Mine is an A4 (letter) size piece of paper and a yellowish colour. Without that and/or the dongle, the software is useless and I hope they did not charge you for it. I am thinking that the person who sold it to you has kept the software installed on their computer and is using the dongle, so it is quite illegal for them to "sell" the software to you without first erasing it from their hard drive.
The Designer 1 USB is a fabulous sewing machine but to get the best out of it for embroidery, you really do need software. If you have no luck with the 3D, then I suggest you purchase Embird (Google for it - should be easily found). This is a very reasonably priced and highly effective program - around $150USD I believe which is a quarter or less than the cost of the Husqvarna software. You can load Designer 1 USB sticks from this program and there is lots of help and tutorials available online. Even better the program is available as a download and you don't need any security dongle, plus you can download it and try it free to see if you like it.