I have an old Lenovo Yoga 2 (i5-5400u, 4GB RAM, 128GB SSD).
This 2-in-1 system does not have an ethernet port and during Debian installation using the netinstall ISO, non-free firmware is needed for the Intel wireless controller.
I went to Debian’s installer page for non-free firmware (for Bullseye) and downloaded the zip file: https://cdimage.debian.org/cdimage/unofficial/non-free/firmware/bullseye/11.3.0/
I expanded the zip all the way into the data compressed folder. Inside that I pulled the
lib/firmware/iwlwifi-1762-17.ucode to the root of my USB installation media.
I booted the Debian installation again. Once it got to the search for non-free firmware screen again on I switched to a VTY so I could copy the file over.
cp /cdrom/iwlwifi-1672-17.ucode /lib/firmware/
I switched back to the graphical installer and chose to scan removable media.
I was then presented with a wireless network list to choose from and connect to then continue on with netinstall.