Please excuse the totally newbie question. Can I connect a PCIe card such as this to the board?
for UP Core you would need a carrier board with miniPCIe slot like this: https://up-shop.org/up-core-carrier-board-high-speed-i-o.html
And an adapter from miniPCIe to PCIe x1
Also bare in mind if the PCIe board requires additional power, you might need to provide that externally.