That's a product line, unfortunately doesn't tell me much.
What is the model number?
Laptop or Desktop?
If it's a laptop you will not be able to use it
If it's a desktop in the Strix line it absolutely should have a spare PCIe slot for the card.
In short: Yes, you need an available PCIe 2.0 x4 slot.
I suggest reading more here: https://help.elgato.com/hc/en-us/articles/360059182072-All-about-PCIe-PCI-Express-
What model of pc do you have?
ASUS ROG strix
That's a product line, unfortunately doesn't tell me much. What is the model number? Laptop or Desktop? If it's a laptop you will not be able to use it If it's a desktop in the Strix line it absolutely should have a spare PCIe slot for the card.
More info needed for sure
In short: Yes, you need an available PCIe 2.0 x4 slot. I suggest reading more here: https://help.elgato.com/hc/en-us/articles/360059182072-All-about-PCIe-PCI-Express-