How do I use private functions/variables in the Javascript module pattern?

I'm reading this article about the Javascript Module Pattern and came across a snippet which claims you can preserve private variables/functions across module files and access them from each other:

var MODULE = (function (my) {
    var _private = my._private = my._private || {},
        _seal = my._seal = my._seal || function () {
            delete my._private;
            delete my._seal;
            delete my._unseal;
        },
        _unseal = my._unseal = my._unseal || function () {
            my._private = _private;
            my._seal = _seal;
            my._unseal = _unseal;
        };

        // permanent access to _private, _seal, and _unseal

    return my;
}(MODULE || {}));

I'm a little confused as to how I go about implementing this, but I think most of that confusion is from not understanding quite how this works; how does it enable other scripts already loaded to utilize those internal values? And how do I add functions and variables within this 'private' space?

My end goal is to provide a sort of 'abstract' function variable that must be overridden in sub-modules, but still needs referenced in the base module's file. Admittedly I haven't played with this much but that's mostly because I'm trying to wrap my head around how the actual implementation works.

Thanks in advance.