Q1: I changed the configuration file to a new trigger mode. The default trigger mode is still used, instead of the new trigger mode.
A1: Make sure your computer is not set to hide the file extensions. Your file is incorrectly named "read.cfg.txt" instead of "read.cfg". Uncheck "hide extensions for known file types" under "folder options" and rename your config file to "read.cfg"
Q2: When I apply power to the module, WITH the microSD card already inserted, the configuration file (read.cfg) stored in the onboard flash memory is used, instead of the read.cfg file on the microSD card.
A2: Take the onboard read.cfg file offline by renaming it to a different name. Now the read.cfg file on the microSD card takes precedence and sets the correct mode. If it still doesn't work, put your read.cfg file on the onboard flash memory instead of the microSD card.

Q4: How do I adjust the volume of the board?
A4: All you need is a small star point screwdriver. The onboard potentiometer used to adjust the volume is the small blue square just next to the headphone jack. Turn clockwise to increase volume. Turn anticlockwise to decrease volume.
Q5: I don't have a 10W speaker on hand, so can I use a smaller speaker like 3W or 5W instead?
A5: You can, but you need to adjust the sound volume to a moderate or even lower setting to protect the speaker from damage caused by the powerful driving from the amplifier of the module.