itch.io

This is generic advice but hopefully it'll point you in the right direction.

In Decker Buttons (including checkboxes) have a .value attribute. The .value can be set to 1 or 0, true or false. If a checkbox is marked that means the value is 1 (true). 

You can have code check whether or not  a specific checkbox is marked and do different things depending on whether or not it is. For example:

if mycheckbox.value 
# some code goes here
else
# optionally you could put some other code that should happen if mycheckbox isn't marked
end

If the checkbox is on a different card (for example, on another card that's named 'options') you may need to refer to it by a longer 'address'.

if options.widgets.mycheckbox.value
# your code goes here
end

Here's another resource about using if statements in Decker. I hope this helps a little!