I suggest revising documentation for SKU 200139, DC Panel Meter (Model 031) (6.5-100V, 20A/2000W). The language follows some non-English conventions and awkward translations, which makes understanding hard for a native English speaker. I edited it to be more easily understood by native English speakers, and to be as clear and concise as possible without omitting information.  (I have three of your panel meters, 1 AC and 2 DC.  Most of these writing changes would improve documentation for other models too.)

Here are some tips for your writers/translators:

• Information about damage and malfunctions are considered warnings.  Label them as such, and put near beginning of documentation. Assume an English reader stops reading instructions before the end if they have enough information to attempt device operation.  Assume user impatience. Warnings go first so they are seen before instructions.
• Warnings and directions in English/western documentation are explicit, and NEVER use courtesies like “please”. (Native English speakers interpret “please” as meaning “optional” and “unnecessary” when used in documentation.  We do not expect documentation to be “polite” or show courtesy.  Courtesies like “please” are reserved for requesting user feedback, encouraging contacting customer service, or voluntary product registration — all things that are not required and most users never do.)
• Instructions in English avoid use of “can”, “will” or “could” when possible. Instructions are typically of the form: “DO this to CAUSE that”, or “to CAUSE that, DO this”.
• In English, “key” (as in words “keyboard” or “keypad”) typically refers to a button on a pad with multiple other buttons, like a keypad on a phone or a keyboard. When a button is by itself or separated from other buttons, it is not usually called a “key”, just a “button”.
• “Long press” and “short press” are confusing because they don’t specify duration of a short press. “Press and immediately release” and “press and hold until” clarifies.

Additional suggestions:

•  Showing where each piece of information (voltage, current, power, energy) is located on the display in the dimension diagram would make instructions clearer.
• Number ranges in English (and other western languages) are written “0.0-999.9W”, not “0.0~99.9W”. In English, electronics informally uses “~” for ranges, but not usually in documents or formal writing. Because the “~” isn’t wholly incorrect, I didn’t change it. However, I suggest you do for improved clarity.

Here is my suggested re-write:

Meter Features:

• Measure voltage, current, electric power, and track energy consumption (with built in shunt)
• Backlit LCD panel displays voltage, current, electric power, and energy consumption at the same time
• Voltage alarm: when the voltage is outside an alarm threshold, the backlight and voltage flash
• Energy consumed can be reset
• Non-volatile memory

Warnings:

• Do not use outdoors! Only suitable for indoor use.
• Do not exceed rated voltage or current!
• Ensure correct wiring!

Display Format:
Electric Power Range: 0~2kW

• < 1kW format: 0.0~999.9W
• >= 1kW format: 1000~2000W

Energy Range: 0~9999kWh

• < 10kWh format: 0~9999Wh
• >= 10kWh format: 10~9999kWh

Voltage Range: 6.5~100v

• Format: 6.50~99.99V

Current Range: 0~20A

• Format:0.00~20.00A

Parameters:

• Operating voltage: 6.5~100VDC
• Testing voltage: 6.5~100VDC
• Rated power: 20A/2000W
• Measuring Accuracy: 1.0

Button Functions:
Backlight Control

• Press and immediately release button to turn on/off back-light. Meter remembers the state when powered off.

Reset Energy Consumed

• Step 1: Press and hold button until panel displays “CLr”, then release button.
• Step 2: When energy is flashing, press and immediately release button to clear energy reading and exit. If button is not pressed in 5 seconds, meter exits without clearing.

Set Voltage Alarm Thresholds

• Step 1: Press and hold button until panel displays “SET”, then release button. “Voltage” position will display overvoltage threshold, and “current” position will display undervoltage threshold. Last digit will be flashing.
• Step 2: Press and immediately release button to increase flashing digit by 1. Repeat as needed. After 3 seconds of no button pressing, next digit will start flashing and can be set in same way. Repeat until all 6 digits are set correctly. Voltage alarm threshold is 06.5~99.9V.
• Step 3: Press and hold button until panel displays “PASS”.  Meter saves settings and exits.