Typically with any PC build, you will need some type of graphics processor to connect a monitor. If your motherboard does not have onboard/integrated graphics you will need a video card of some sort.
As far as Thunderbolt card, for a PC that doesn't already have a Thunderbolt interface built in, you will need to verify that the motherboard does indeed support Thunderbolt and has a Thunderbolt connector on the motherboard itself where a Thunderbolt interface card will need to be plugged in. If those conditions are true, you will need a Thunderbolt interface card that plugs into the PCIe slot of your motherboard as well as plugs into the Thunderbolt port on the motherboard.
