Hi,
If you activate the "Characteristics dynamic display" setting of the HikaShop configuration, only the first characteristic will appear and be selectable when reaching the product page. Then, when you select something in that characteristic, the second characteristic will appear, and you'll be able to select something in it. And then same for the third one, the fourth, etc until the last one which will then refresh the information of the product with the selected variant's information and display the add to cart button for that variant.