To read the full guide with pictures, click here: Anviz EP300 Basic Guide
Wherever an FN/Input appears alongside the Esc/Back prompt at the bottom of the screen, you may input characters besides numbers.
To do so, when editing text, press the FN button to bring up the advanced input interface. You may press the Left/IN and OUT/Right buttons to cycle through the character types: alphabetical, numeric, special, and Chinese.
Alphabetical: Most numbers on the keypad have letters associated with them. To get a letter, press the number it is associated with. It will then show a selection of lowercase and uppercase characters you may choose to input. Press the number associated with your choice to finalize the letter in your input.
Numeric: This is the same as normal input.
Special: You will be given a selection of up to 9 special characters to choose per row. You may press the number associated with the special character of your choosing to input it. You can cycle through the rows of special characters by pressing 0.
Chinese: You may combine numbers to get different selections of Chinese characters. When you get the selection group you want, you may press OK to keep that selection group, then press the number associated with the Chinese character you want to input.
After you are done with your input, you may press OK to finalize and remove the advanced input interface.