Is there a way to set defaults in TinyMCE that a new user can do?

I'm using "Protostar.

I would like to default to the font "Tahoma" at "12 point".

I found a couple of references to making similar changes in "Beez3" but nothing for "Protostar"

What I was able to find was way over my head; the posts said things like:

---------------

$('#content').tinymce({
setup : function(ed)
{
ed.on('init', function()
{
this.getDoc().body.style.fontSize = '12px';
this.getDoc().body.style.fontFamily = 'serif';
});
}
});

--------------------------------------------------

I have no idea what this is saying , how it gets me Tahoma as a default font, or where to do what it suggests.

Is this a cut+paste into a file someplace? What file are you supposed to modify. This solution was from 2013, so I don't even know if it's still correct, nor can I determine which template [Beez3, Protostar, etc] this applies to.

Thanks for any help you can offer.

Mark