If you haven't done it already, you'll need to mash a video with the Mash button at the bottom of the project's grid screen. Here's a tutorial on how to mash a 1SE video.
Now you have this beautiful video, and you want to share it. When you mash a video, you'll see a blue checkmark button (iOS app) or a "Save & Share" button (Android app) at the bottom. Tap it and on the next screen, select the "Share" option.
It's also okay if you'd like to share it out later. You can go into the Photos (iOS) or your Gallery (Android) app on your phone and find the 1SE album. Inside that album will be your mashed 1SE videos, which you can share, delete, or view.
But I don't want to share it publicly, and it's too big to email! HELP.
If you don't want to share it on social networks, you can use a service like iCloud Drive, Google Drive, Dropbox, or a website like WeTransfer. These will allow you to upload the videos to the cloud, then send a link to someone or yourself. Doing this will keep the video files from being compressed or run into any size limits with email clients.
One other option is to use AirDrop (iOS) or Bluetooth (Android) technology if you're trying to send it to your laptop or someone close-by.
Be mindful; mashed videos can take up a lot of space. If you're tight on storage, it's best to delete a mashed video once you've shared it or moved it to another device.