How do I lift dump bed?!

Hi - Sorry for the newbie post. I recently inherited a truck and will be selling it shortly, however, I cannot figure out how to raise the dump bed. The previous owner showed me but now I cant recall! Its a 1980 Ford 3000 with two axles. There is a switch that says in out on the dash and there is what looks like a stick shift where a manual shift would normally be (its and automatic so I know its not the stick shift). I have no idea whether to have the switch flipped to in or out. I have no idea whether to put it in neutral or drive (it has no park) ...and I can't get the shifter thing to move at all. (Maybe it has to be in neutral or drive with the switch on in or out...like some combo of those will give me ability to move the shift-like stick? Any input is welcome. I don't have pics of the interior, but will take a few this evening. Here is a pic of the truck:

 

Hi - I apologize; I got busy with kids coming in for the wknd. Thank you much for these replies! I will definitely respond with results tomorrow! Thanks again!

 

Again, thanks for your input. Unfortunately I had no luck. I tried the various combos above...and it does help me to know that the 'PTO' switch should be in the 'in' position. When I do put it in this position, the red light lights up and makes a buzzing sound, presumably as a caution signal that the dump bed can be activated. The problem I'm having is that the shift to make the bed raise and lower won't budget. At all. Its almost as if its locked due to not engaging some other mechanical lever. There is a metal lever outside the bed near the door that unlocks the bed door so that dirt can flow out when raised, but I have tried this both in open and locked position with no difference. (Plus I can see the mechanics of the lever do nothing more than engage the back door.) One thing I noticed is that the dump stick is threaded at top and is missing the ball or even an additional lever attachment. Maybe it requires so much force that additional length provides the leverage needed to move it? (I pushed as hard as I could to get it to move in both Neutral and Drive positions with no movement...tried pushing forward toward dash and back toward seat.) I can't tell if the dump mechanism is engaging when I turn the PTO on in drive and then move to Neutral. There is no audible change in sound or mechanical feeling of popping into gear. If you have ideas, I'm all ears! Thanks again for previous suggestions! Btw, I plan to get a long piece of metal pipe to extend the length of the dump stick to see if the added leverage is what is needed. Thanks again for your help. Pics attached...

 

Success! It was just a matter of getting enough leverage on the stick to push it forward; 18" pipe did the trick! However, that was just the final step. ...I could not have done it without your input. And I certainly would have risked damaging the PTO upon engaging and lowering without knowing whether to have in or out. Thanks so much! -S