You’re really close with this. Once you’ve defined your “Source” (as
alert_12hr), you then reference that as
value in the “Cell Template”. You can read more about configuring a Device State Table block, but the relevant bit is:
In the Cell template, the name variable is available, as well as a value variable, which is the actual value backing that cell.
So for your situation, your “Cell Template” might look like this:
Those dummy images are for green and red blocks respectively.