There like a rubix cube...........only with ball bearing.
With the cv off and in yer hand you can push the cage round until one ball is clear, pop it out with a scredriver and repeat. If you go directly oposite and remove that ball the full cage shoulod come free and you can pop the rest of the balls out easy enough.
You'll notice the joint is...........cut with a thick space then a thin between each recess where the balls sit, when building it back up it'll only go in one way iirc. Place the empry cage in the cv at 90 degrees, then place one ball in a rotate it into the recess, push it right down and place the opposite in and work your way round.