Question about DC ports 1-3

[zee_zout]

So they add an extra layer of protection but can also be used on their own if you run low on sensor ports. For example, maybe you have a light in a cabinet and you want it to come on when cabinet door opens and off when closed. All you need to do is leave the DC port turned on in reef-pi, add any on/off switch wired to backup float port will do the switching.

I have a switch on my door, but haven't found a good way to use this in reef-pi.
But your tip is exactly what i needed 

Thanks!