I still see that you aren't understanding. I will make like a sort of steps and maybe then you will understand
1. Open the Previewer ,click File/Create a derived product
2. Put the code of the clothes for example : 198412
Then the previewer will download the clothes.
3. Click File/Save as
Then save the 198412 product on your computer
And here's the problem I was talking about before.
How to load the downloaded product in the inventory.
I hope you understand now.