Confused about CAN receive rules & buffers

My needs are simple.  I want to receive all CAN messages on the bus.  Therefore, it seems like I only need one receive rule (with RSCAN0GAFLMj=0 and GAFLDLC=0 so there is no filtering).

However, I'm confused about where the incoming messages will be placed.

I think I'm missing something fundamental about how receive buffers (and the FIFO) works.  Is there a good explanation for all of this somewhere?

Thanks.

RSCAN0GAFLMj