In Switcher, tap the icon in the upper left (3 parallel lines).
Now tap on Recorded Media.
Scroll through and find the recording you want to transfer. (The most recent videos will show up at the bottom of the list).
Now tap the transfer icon towards the upper right.
Choose "Send to Photo Library" and the transfer will begin.
Your recording will now be available on the device's Photos app.
For bulk moving files, we recommend using a computer and iTunes. Check out this tutorial for help with that.