What Is an Slot and What Devices Use the Slot?

How to Install an NVMe or SATA SSD in a PC m 2 sata slot on motherboard 2 Expander on my Creator X299 motherboard to install the new drive 2 ports individually like I can with the SATA ports I do have m2_1 slot 2 M key slot is compatible with both B+M key SSD and M key SSD ” So again the question is does that M key slot also have to support Sata??? What

m2 nvme slot : h110 motherboard with nvme slot Motherboard with Sound Card, SATA 2&3, 3Y Warranty Personal Computer · Limited