[Kube]

Generally you would disconnect the hot side. In other words, the negative post.
With this type of disconnect, simply back off the green knob.
Just a word of caution for you... if you have trouble on the road (what seems like a dead battery) look at this disconnect. they are not of very good quality.
The old ones that look like this were solid brass. Those worked well. Like most things, the manufacture found a way to make them cheaper while sacrificing quality.