I've been working on this build the entire weekend and It's been a terrible experience through and through. The instructions aren't 100% clear, the vendor that was chosen had made incorrect and/or too short of parts, the "Recommended LCD 'Upgrade' " is barely visible.
Despite all of the physical problems, I keep running into errors from Pronterface with non-stop beeping that can't be turned off. Example:
Error:MINTEMP triggered, system stopped! Heater_ID: bed
[ERROR] Error:MINTEMP triggered, system stopped! Heater_ID: bed
Error:Printer halted. kill() called!
[ERROR] Error:Printer halted. kill() called!
Is there any sort of troubleshooting guide for error messages?
Check that the thermistor is firmly plugged in, also check it's not shorting at where it's mounted, remove it from the bed and check if it's still working and then carefully re-install making sure none of the exposed ends of the thermistor (near the bead) are touching each other.
Otherwise please get in touch if you have a bad thermistor, we should be able to replace it for you.
Verify that your hotend thermistor is plugged into the main board. I had the same issue and it turned out the my thermistor cables (that I had to modify because the original were too short) had become unplugged from the board.
As for the LCD, have you adjusted the contrast? There's a small plastic screw on the back that adjusts the contrast.
Edit: I just saw that it's calling out your heated bed specifically. Make sure the heated bed thermistor is plugged in correctly.