Jump or climb at the end of "The prison"

[k-risc]

I am stuck at the very end of the first chapter "The Prison". I pass the room with the eye, into the big room with the bridge, run over it, make the jump over the gap, and then are supposed to jump or climb onto the box/crate, so I can jump towards the exit on the right side. But whatever combination I try, I just can't get onto the box. It starts getting annoying as I always have to re-start before the room with the eye, and first have to pass that room again and again in order to get to the bridge.
Which buttons do I have to press in which order?
Often after I tried to jump with the "A" button, I afterwards seem to be so close to the box that pressing "A" once more yields no jump. I first have to move away and apporach again, so that pressing "A" yields another jump. But the child never holds onto the top ege of the box and pulls itself up, as I have seen it in walkthroughs.
There is no other box of this size just lying around elsewhere at that stage of the game, so I cannot parctise and try to find out what I have to do.

[Dottoman]

For higher ledges you need to jump and press and hold the "grab" button. That is whichever button you use on your controller to pick up items and carry them around or to grab and pull boxes.

So jump, hold down the "grab" button to hold onto the ledge, then press up/forward to climb up the ledge. You'll be doing this quite a lot. Good luck!