Make the bootable usb installer:
Format an 8 GB (or preferably 16GB) USB3 drive which should be called Untitled and formatted as Mac OS Extended (Journaled). The installer should be called Install macOS 10.13 Beta.app and should be in your Applications folder.
Run this in terminal and wait about 20 minutes:
sudo /Applications/Install\ macOS\ 10.13\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ macOS\ 10.13\ Beta.app --nointeraction
Format an 8 GB (or preferably 16GB) USB3 drive which should be called Untitled and formatted as Mac OS Extended (Journaled). The installer should be called Install macOS 10.13 Beta.app and should be in your Applications folder.
Run this in terminal and wait about 20 minutes:
sudo /Applications/Install\ macOS\ 10.13\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ macOS\ 10.13\ Beta.app --nointeraction