Siguid,
Bart suggested shade, since the tree will stand a better chance of recovery with good light, not direct Sunlight. This would put extra stress on the tree, since it will transpire more water and put a greater demand on the roots to supply fresh nutrients and water. If the roots are weak, they can not supply this demand and the tree will deteriorate and even die.
Keeping the tree in the shade allows the roots to establish and start growing, without this drain on them. In 2 to 3 weeks, start introducing it to more sun but keep the soil "just moist". Providing there is fresh growth over the same period, it will start "drinking" more as the canopy fills out.
I would suggest leaving any major work till next Sping. Just let it grow for now, since this will also help strengthen the roots.
Post an update in a months time and we will try to suggest a plan
Good luck,
Ian.