How do they do the dinosaurs in a movie like Jurassic World?

they paint the 3d model, and specify virtual bones and muscles and define which point of the body is affected how much by which bone.
Then they animate with basically stop motion techniques, e.g. specifying at which frame the bones are in which position.
The computer does the interpolation between bone positions to smooth out the transition.
certain parts of the model are animated directly in addition to the bones where needed.

there are a few physical models in the movie, the apathosaurus head and the velociraptor heads for the scenes in which their snouts are caged.
the rest is cg.

In the original movie, they had a full size animatronic, hydraulic T-Rex, a full sized animatronic Triceratops, a massive animatronic brachiosaurus head, and the raptors where guys in raptor suits.
They used CG only for far away shots.
And the practical models look so much better and more real than today’s cgi.

Here’s an article that you might find interesting.