This project makes a wifi router out of an ASUS PCE-AC88 wireless adapter and your Ubuntu Linux computer that can exceed top of the line routers.
Instead of buying a gaming grade router or another computer that you install openWRT on, follow this project and put the savings towards upgrading your main computer or modem.
The adapter needs to be added to a PCI slot and the wireless antenna needs to be connected to the adapter. If your computer does not detect it, you may need to re-seat the adapter in the slot. If you can't detect wireless networks after installing the firmware below then this is probably why.
For your computer to use the wifi adapter you need to add the missing firmware that Asus won't provide.