Hi there
I use a proggie called OFP script editor
quite obvious it is a utility that helps you create scripts.
Maybe you do not wanna fool around with scripts yet as you say you are new to all this, but it has a great option for briefings too.
incorporated in this program is the Create Briefing File Wizard, which lets you create overview, briefing, objectives and endings in a nice pop up under 4 tabs.
You can just add text to the boxes in the pop ups and insert markers aswell and when you are done use the browse button on it to put it in the correct folder. It is quite easy to use too.
Dunno if this works for you but here's the URL:
http://ofp.gamezone.cz/editor/OFPSEdit.zipMadFred