Which slot should I use for my SSD?

You could also get a adaptor to plug into the pci-e ports on them motherboard You will get same speed and stability with it And you CAN choose

Supports 7th 6th Generation Intel® Core™ Processors; Dual Channel DDR4, 2 DIMMs; Ultra-Fast with PCIe Gen2 x2 & SATA mode support; 8-channel HD Audio

m2 slot mainboard 1 SSD Slots 5 x · 4 x · 3 x · 2 x · 1 x Graphics Output HDMI AMD B550 AORUS Motherboard with 12+2 Phases Digital Twin Power Design

m2 nvme slot And also if the slot on the motherboard takes a B key, M key or a B+M key for the SSD?? If is not possible then