Assuming you mean hot plugged devices (thumb drives and external drives) KDE mounts them under /media
If you are expecting them to auto mount, KDE distros often don't have that enabled by default. Though I think Kubuntu has that enabled by default now so maybe that has changed. Go to System Settings -> Hardware -> Removable Devices to adjust the automount settings defaults and per drive settings.
If you don't have automount enabled you probably will need to browse to them in Dolphin once to get KDE to mount the drive first.
Assuming you mean hot plugged devices (thumb drives and external drives) KDE mounts them under /media
If you are expecting them to auto mount, KDE distros often don't have that enabled by default. Though I think Kubuntu has that enabled by default now so maybe that has changed. Go to System Settings -> Hardware -> Removable Devices to adjust the automount settings defaults and per drive settings.
If you don't have automount enabled you probably will need to browse to them in Dolphin once to get KDE to mount the drive first.