my adaptere is plugged in but nowhere to be found in the mac

Be sure in Finder preferences you have to show external disks on desktop and in sidebar and then when you insert a card it should show up in Finder and desktop. If it does not then perhaps you have a bad reader or SD card.

What adapter are you talking about? All plugs are on the side of the Mac. that would connect any hardware with an adapter. Connected hardware will show on the Mac in Finder or on the desktop.