how do i create an animal from the EA t-rex? also, how do i mesh?

They are many tutorials in Designing Centre, there is a link in the affiliates box of here. Is to difficult to explain how to mesh in a post. And all the EA animals arent mesheable, only the Ankylo and the DD Styracosaurus, Tyrannosaurus Rex, Triceratops and Carnotaurus, the Styracosaurus, Tyrannosaurus Rex, Triceratops and Carnotaurus form EA arent mesheable