Which sentence below shows correct use of an em dash?

i just watched the lord of the rings—my favorite film trilogy—with my friends.
i just watched the-lord-of-the-rings my favorite film trilogy with my friends.
i just watched the lord of the rings my favorite film-trilogy with my friends.
i – just watched the lord of the rings my favorite film trilogy with – my friends.

Check for errors. flora and fauna e to each of its four parts of the british isles 1. the warm and wet elimate of great britain is very good for plants. 2.that's why the country looka like a big beautiful .3.centuries ago there were a lot of foresta in the british isles, but now garden. 4.you can find big foresta only in a few parts of the country- the north of scotland and the southeast and southwest of england. 5.the most com- mon trees in england are onks, elma and beeches while scotland han a lot of pines, firs and birches. 6. the fauna, or animal life in the british isles is like in the northwest of europe.