DO NOT INSTALL ON A PC! USE VIRTUAL MACHINES! GREENTEA OS IS UNSTABLE RIGHT NOW!
Otherwise, installation should be straitforward and self descriptive:
- Download or build the .iso yourself
- Write it onto the flash drive with software like Rufus
- You should check the manufacturers articles on how to enter BIOS on your system
- Reboot the computer
- Enter BIOS or boot selection menu
- Choose something that resembles "Greentea OS" or USB drive of the corresponding model
- Viola, enjoy
If you have any problems, take a photo of your screen (it should contain some info that is useful to resolve the issue) and send it to the developers.