M2 Heatsink That Fits Behind Motherboard?

All of the motherboards with more than 1 slot that I have checked out appears to only have 1 slot connected directly to the CPU,

So I have a bit of confusion here on which Slot do I use Motherboard manual says following -For 3rd gen AMD Ryzen Processors, the _1 supports PCIe

eltz slot While the traditional SATA SSDs can leverage both the ” form factor as well as the slot on the motherboard itself, the NVMe drives are

tws slot RF PYJFPM–Hard disk SSD m2 on the motherboard background RF 2HBD6BR–The hand holding the computer's mainboard and Solid State Drive RF 2K4W46M–