How are these effects created?

Have a look at the youtube video. How would I create the effect at 1 min 23 Girl(baseball cap) facing herself , is it a simple split screen of her shot from 2 different angles?? And I min 44 as she morphs out of herself under a pier, again it's split screen but how does one get that morphing effect is it created due to the way she is shot originally??

Simple composite. First one, placed a copy of the clip on top of itself, reverse it (specifically use the Flipped filter), offset the Position X axis a tad, and lower the opacity of one or both.

The second one, there are mirror effects that do this, prebuilt. But you can create it on your own by simply doing what I mentioned above, but leave the opacity of both at 100, and crop the sides of each so they fit together along the needed plane.

Great thank you, i'll try those out.