The steps for installing IodeOS have been changed / simplified for official devices. Unfortunately, the simplified steps do not work (yet) for my unofficial builds, so the instructions in my post about the build are now slightly misleading
To install the recovery image
Follow the Booting a custom recovery using fastboot instructions on the LineageOS Wiki. (Note that the recovery image to be used is now named boot.img):
https://wiki.lineageos.org/devices/sunfish/install#booting-a-custom-recovery-using-fastboot
To flash the IodeOS build (latest version is iode-4.1-20230420-sunfish.zip)
Follow the Installing LineageOS from recovery instructions on the LineageOS Wiki:
https://wiki.lineageos.org/devices/sunfish/install#installing-lineageos-from-recovery
For the latest build, the command to sideload the IodeOS ROM is
adb sideload iode-4.1-20230420-sunfish.zip