Backing up is like making a copy of the things that are important to you. It's like having an extra copy of something in case it gets lost or broken. For example, if you have pictures stored on your computer, you can back up those pictures to an external hard drive or a cloud storage. That way, if anything happened to your computer, you'd still have the pictures saved safely on the other drive. Backing up can also help protect against viruses, hackers, and other online threats that can damage your files.