Adjusting tilt type garage door?

Our garage door which has a auto opener on it has started catching on the bottom right corner. How do I adjust? More tentison on left spring or less on right? Both?

I doubt its the springs, more likely a bit of movement has occurred in the door framework.

Just be aware that the door can give a severe injury if you undo the springs.

If it has lag bolts holding the track to the framing, check that one hasnt loosened.
You may be able to move the track slightly to compensate. Also check the track at the diagonally opposite corner, as it may be throwing the whole thing out.

What is trying to be achieved is parallel and square in the two planes,ie in the shut position and when up in the open position.

Don't p*ss around with the tracks.
If the door/tracks are adjusted right, then the wheel should be able to be turned with your fingers when the door is in closed position. If the door has dropped, then one or both may be tight in the tracks - not how they are supposed to be. They should not be supporting the door in closed position.

Typical things which will cause a corner to catch are stuffed bushes in the pivot on the arms (some are replaceable - some you need new arms), or the arms will have come loose on the jambs, or the facing jambs may have twisted, or the garage floor lifted/moved, or the garage itself has twisted. Another is old locks (not usually needed when an auto is fitted) which have been disabled by pinning back the cord, the cord has stretched or come loose, and one of the locks is catching on the flashing. Could be a stone on the floor too.
What to fix and how to fix it depends on identifying what the problem is. Could be as simple as re-attaching / straightening the jamb facing, or tightening the bolts (make sure they are secure not in rotten timber - add extras if needed) holding the arms to the jamb. OTOH the door might need to be lifted a few mm on one side, or arms replaced. The doors are usually square (not always though), so looking at how it lines up when closed might give some clue as to what's going on.

Yes - if p*ssing around with the brackets, arms etc, unless you've removed the springs first, don't touch anything / get close to the spring when the door is closed (and spring stretched). More recent doors tend to have washers on the arms larger diameter than the loops on the spring, and "pig-tail" hooks on the bottom of the spring - so if a spring breaks it hopefully won't go too far.

whole thing is giving me the shits! Spent the whole afternoon playing with damn thing. At the point where a bigger hammer is required. Pivot brackets were loose so bigger bolts pulled it up tight to door frame. Made it worse! When fully open all level and square But during close goes spastic and jambs on one lower corner. Now bouncing and won't close, having to pull cord and close manually. I am thinking semtex will resolve issue.

might be you need to loosen those bolts again and put packers behind the frame, perhaps all that happened isf the packers that were in there have fallen out and been swept away

Packers under the arms (if needed) are more likely to be needed to keep the door centred as it's going up or down (ie - as the arm arcs) - rather than jamming in almost closed position. Something else is the problem - and I'm not going to be able to diagnose it on a forum.
OP should give up if they've already spent hours on it - call a specialist on Monday.

On a previous house, the garage door would jam in one corner, the cause was a nearby tree, its roots were lifting the corner of the garage. Also could be ground subsidence /slumping.