Compute modules witout eMMC ("Lite" versions), boot from the SD card in the CANOPi socket.
Compute Modules with integrated eMMC flash can not boot from an SD card (this is a CM4 hardware limitation), therefore you need to programm the integrated eMMC flash.
Basically the official documentation applies, which you can find here, or in Jeff Gerlings nice tutorial.
These tutorials assume you are using the official Compute Module 4 IO Board.
In a nutshell, you need to jumper the nRPI_BOOT / disable eMMC boot jumper connect your board to our computer where you ran a small piece of software, which basiclly turns you compute module into a (slow...) mass storage device exposing the eMMC flash.
So you are wondering, where to find the nRPI_BOOT signal to repeat this trickery directly on a CANOPi?
Glad you asked:
You just need to put a 1.27mm Jumper over the marked nPIREBO pins.
Do all the flashing as per the linked documentation above, possibly not forgetting to do the neccessary Raspberry OS modifications, remove the jumper and reboot.
Word of warning/friendly advice: Putting the jumper can be tricky and requires a steady hand. Using pincers is recommended. Obviously, only try to set/remove the jumper when the CANOPi is powered off.