First thing you will notice is that it is split into two - Bank 0 and Bank 1.
Bank 1 is used to control the actual operation of the PIC, for example to
tell the PIC which bits of Port A are input and which are output. Bank 0 is
used to manipulate the data. An example is as follows: Let us say we
want to make one bit on Port A high. First we need to go to Bank 1 to set
the particular bit, or pin, on Port A as an output. We then come back to
Bank 0 and send a logic 1 (bit 1) to that pin.