You need to get a pry bar and get it in the slots that it has and try and flick it out if you get me, or just get a flat chizel and hammer and whack it out. either way it does just pull out, just needs a shock.
When you get them out you will see the snap ring on the splines that came out of the box. Its open ended and I find that when you fit the cups back in its best to leave the open end downwards to help prevent it being damaged.
Big screwdriver in the notches for the CV boot clips, couple big whacks with a hammer and you're done. Prybar between the box and the CV cup can damage things quite easily if you're not careful!