Ryzen 7 1700 Thunderbolt 3

You can't.

Thunderbolt is based PCI-Express protocol, but designed for connection with external or peripheral devices, such as Smart TV or so forth. I heard there exist some Thunderbolt adapter, which could be inserted onto the PCI-E 3.0 x16 port, with which you could extended your Ryzen based system with thunderbolt support! Wish you have a good journey on the AMD Ryzen products! 

Wish I could have already solved your problem...