Answer:
Bend knees 90 degrees( kind of like a squat) this puts the least pressure and strain on your back. Place hands to pick up box (depends on the box, but mostly at the sides and hold from below) slowing straighten legs/knees from the positions and then proceed to place it on table. If the table is lowers than your level of holding the box, begin to bend knees to rest the box on the table.
Step-by-step explanation: