Don't Install if You Aren't Prepared
Are you ready for the macOS 10.15 beta? If you can't answer with a resounding yes, then don't install this beta yet.
You need to take steps including a Time Machine backup and planning on where you will install the macOS Catalina beta before you even download the first part of this update. A backup protects your files and it makes downgrading from macOS 10.15 to macOS Mojave much easier.
You should also do research into the macOS 10.15 beta to learn how it runs on older Macs and research any app or hardware issues that other users are having before you take the plunge.
Here is a list of the things you need to do before installing the macOS 10.15 beta. Walk through this guide before you install the beta and you will be better prepared. Also, make sure you have enough time set aside for the installation.