1.) Format an SD card to FAT32. 4GB minimum( I generally use 16 and 32 cards), Class 10 or better recommended. The faster the better.
2.) Download and extract the file, the extracted file will be an image. I use 7Zip for extraction.
3.) Burn the image to the SD card. I use HDD RAW(portable ver.). Programs like Rufus or Win32DiskImager, etc should also work. Caution with HDD RAW, make certain you select the SD card as the target, HDD RAW will write over anything. It does have a couple of confirm notices, but be careful anyway.
To Run with prepared card: A few things take place, it does not just boot to Linux first go round.
1.) With the TV box running Android, insert the prepared card in to the box's SD slot or use a USB card reader.
Note: I like to use a card reader with activity LED, so I can see something is happening. The first boot can take a few minutes and the flashing LED is reassuring.
2.) At Android/Settings/About Device/System/updates.
-From the Update and Backup App, under the UpdateLocale section, click Select, select aml_autoscript.zip, click update.
Note: Leave "Wipe Data" and "Wipe Media" unchecked/unticked. To be clear, do not use those options
-The TV box will reboot, it will do so a couple of times.
-Eventually you will see the initial login prompt.
Initial login credentials, See here for login info on the different images. Latest images will also be at that link.
-You will be asked to select a new password, do so. You will be asked to create a new User and P/W, do so.
-The box will reboot, this boot will be a bit slow, but ultimately should bring you to the desktop.
If the card's available space does not get expanded, use gparted(may need to install) to expand the Ext partition to fill the card. A video to show how to use gparted for this, has been kindly provided by balbes150. See video here.
More info can be found in this Khadas thread.
Let me know if you have questions.