i am trying to install libreelec on my sdCard so that i can boot directly from it, i already booted the installer form my USB stick but i can't find my SDcard in the devices list, only the HDD on my computer i am using for this task.
There is no real installer for SDcards, there is only such a thing for LibreELEC's Generic build.
All others are simple disk images, which can be written by any disk writer software.
Finding devices could be done by for example the mount command, as all devices should be auto-mounted.
Else, try the dmesg listing.
try using a usb to sd card adapter