Getting your 1SE to a new device is super easy! The first step is to make sure you have an iTunes backup with 1SE on it. The best bet is to do one last backup on your old device. Sadly, there's not a way to view what's inside an iTunes backup once it's done. So best to be safe and do one last backup!
Once you have your new iTunes backup, simply select to restore from iTunes on your new device. It's one of the first options on a fresh new OS install. Then you'll need to plug in your phone into your computer for the next steps. Make sure you have iTunes opened on your computer.
Select the most recent backup that has 1SE in it and hit "Continue". Then you'll need to enter your iPhone password. That's it! The restore will show you a time estimate. Hang back and wait for the restore to finish.
Want to use iCloud to restore instead? Here's how you restore using iCloud.
Want to learn how to backup your 1SE using iCloud or iTunes? Here's how to backup your 1SE
TIP: It's very important that the backup you restore from includes 1SE. Without it, your 1SE won't be uploaded to the new phone.