A UART is normally either RS232 (12V system) or RS485 (5V system).
The problem is that normal and Chineese usually (I almost said “normally” 
) don’t go together. So you will need to find out what Daly ment with their UART port.
I suggest one of these multi converters like https://www.robotics.org.za/TEL0070 that you can test with until it communicates.
If you know the ground pin, then the next 2 will be RX/TX (you can just test which way around) and the last one will be the positive pin. Don’t connect the positive pin as the BMS and the USB converter will both have power already.