New build compter only seams to work with RAM in DIMM-slot B1

How to tell what kind of RAM you have what is a dimm slot DIMM physical id: 3 slot: ChannelB-DIMM1 Here in my system I have 4 memory slots in which currently I am using only one slot In what is a slot drain Support 2-DIMM DDR4-1866213324002666 up to 32G maximum capacity; Support 12 x PCIe slots; Support Connector; Support HDMI Connector PDF

what slot machines hit the most DIMM stands for Dual In-line Memory Module and they are the long slots usually arranged in groups of 2, 3 or 4 on either side of your CPU and