Greetings Lucas1071,
We’ve got a few resources to help you get your device updated.
First and foremost, please make sure your computer’s operating system and iTunes are up to date. This article goes over how and it can vary depending on the source of iTunes - Update to the latest version of iTunes.
Next, here are the steps on how to install an iOS update to your iPhone from iTunes Update your iPhone, iPad, or iPod touch with iTunes. The article also has a link on how to create a backup of your device, which is recommended prior to installing any update.
Should you be encountering any error messages or issues while updating via iTunes, these next two articles can be helpful as they begin with some general troubleshooting steps and go further to address specific error messages:
If you see an error when you update or restore your iPhone, iPad, or iPod
iOS update and restore errors
If the issue remains unsolved, or you’re seeing an error not there, please tell us more about what’s happening.
Thanks.