If it's mechanical, not hydraulic, it's not going to have a jog option, and I don't think flipping the motor on and off is going to do what you think it will.
On the shears I've worked with, there's a hex in the end of the motor shaft (opposite of the gearbox - outside end of the motor) that you can turn with a ratchet. There should also be a way to manually engage the clutch - on my Niagara, removing a cover gets access to the clutch engagement linkage - just push the linkage in by hand.
I've never heard of that brand, much less seen one in the flesh, but regardless, there should be some way to engage the clutch and spin it over manually - just need to poke around and find what it is.
Both of those nuts are on the same threaded rod, right? Can't see if there's a gap, or if that's a shadowline. Assuming those are what we think they are (can't really see what I'm looking at in that picture), then tightening one should move the bed forward, tightening the other should move it backwards. Better pics would help. It's possible those are something completely unrelated, and the nuts we're looking for are under the bed.
Regardless you will have to loosen the side bolts, as they're what hold the bed position fixed, otherwise you'll never get the bed to move (they also hold the bed to the legs, so just crack them loose, don't take them out).