sudo dd if=debian-11.11.0-amd64-netinst.iso of=/dev/sdX bs=4M status=progress
Debian 11, codenamed "Bullseye," is a Long Term Support (LTS) version. Because it is an older release, you must look in the "archived" section if you need the specific 11.x version, or use the "oldoldstable" links. download debian 11 iso
Once verified, write the ISO to a USB drive (minimum 2 GB for netinst, 8 GB for DVD). sudo dd if=debian-11
https://www.debian.org/distrib/