Assuming most junis in a can would need root work done to ge it in the bonsai pot, my advise would be leave it alone now until next early spring. Then begin to style the branches and possibly trunk.
In the mean time, take some time to discover juniper bonsai, thier hortucultural needs, and how they should be trained for bonsai.
If the soil you used is a potting soil you will need to be carefull as far as watering goes, it needs to dry down(not dried out) then be watered again. The soil we use isn't really, read up on soil recipies, you should find enough to keep you busy and form a bunch of questions.
I suppose you could wash off the remaining rootball and put ina draining bonsai soil, but you have done a bit much already it looks like.