Powering a Radeon R9 380 from motherboard, which cable?

I bought a used Radeon R9 380 for a project and it only came with the card. I have an Asus Prime Z270-A motheboard that appears to have an 8 pin socket at the top of the board labeled "EATX12V" and then a 24 pin socket on the edge that I am sure is for normal power hookup to the power supply. My Radeon card didnt come with any cables but has 2 6-pin sockets on it so I am assuming it will need 2 6-pin power cables. My question is, which cables do I get to power it and do I need to have separate power out of the power supply for these, or is there sufficient power on the mainboard and I simply need to buy the right cables? Thanks!