Using your photo above, you have Channel 25 in the A Bank and VFO in the B Bank
Hit the FUN button to enter Menu Mode and use the V/M and Main as up and down keys to run to Menu 19:DSPSUB.
Using the Up and Down arrow keys your selections in this menu 19 are: Off, FREQ, VOLT and it looks like you are in FREQ mode in Menu 19, which is correct for dual monitor. Hit the FUN button to exit Menu Mode for now.
Now Hit the Main button to swap the B Bank VFO into the top (main monitor) and A Bank Channel 25 goes to the bottom (secondary monitor). You can now exit VFO Mode and have the B Bank enter Channel Mode by hitting the V/M button and then select your secondary monitor channel using the Up and Down Arrow keys.
Hit MAIN to restore your A Bank Channel 25 to your Primary monitor and the newly selected B Bank Channel goes down to the Secondary monitor.
Unless you find a way around this upcoming problem that I will note, I do not like this feature because I find that whichever channel receives a signal first will take priority in the receiver.
So if I am listening to a conversation in the A Bank and they let the carrier go and at that moment someone hits a carrier on the B Bank Channel, it will take priority on my receiver and I cannot hear the other party's response on the A Bank.
Maybe there is an option around this, but I have not yet found it, so I go back to Menu 19:DSPSUB and turn it to OFF and just use the single monitor.