It is pretty different. There is extra stuff in the EF at the beginning and end, like at the end of every mass the priest will recite John chapter 1 (the word was made flesh and dwelt among us) etc. Most of the actual liturgy is similar, like the prayers, the order of the readings, etc. but there are extra prayers mixed in throughout, like the “domine non sum dignus” 3 times by the priest before consecration, etc. If you have only ever been to the ordinary form, then you may have a hard time knowing what part of the mass you are at unless you have one of the little books to follow along with.