there are many infos about this theme and each write and describe CAN 2.0 sometimes on own way.
Because esp32 does support CAN 2.0 - it is a good time to start in the meantime for read in in the base of CAN 2.0
there are many docu - CAN 2.0A & CAN 2.0B and so on - on the net so only this small spec CAN 2.0 i append here for guys without knowledge in CAN for step by step over Frame, Remote Frame, Extended-CAN-Frames and so on. Hope this helps to start in.
there is a german intro in CAN 2.0 that describe CAN simple way too. , complex (ger) Diploma work is here
here is example an english intro
Yes - ESP32 CAN
best wishes
rudi
edit:
because many documents hidden/not online just in time too :
have phun in archive