Yes there is one - just click the folder where your game is installed - the image below is my CMFB install, the tutorial is the first item underneath the mod tools folder:
As to briefings and graphics - it really is a matter of taste. I knock up all of my briefing images in Powerpoint, screen grab them and resize them in simple old Paint - I know lots of people use photoshop and very fancy drawing programs for their briefing graphics but I haven't got the time, energy or inclination to buy these programs and learn them. You are free to disagree with me but my nuts and bolts Powerpoint/Paint approach produces results that I'm satisfied with and having released countless missions across four of the game's titles I've yet to have anyone say that the graphics were cr@p.
To illustrate the point, here are some examples for a mission based on the Battle of Ap Bac during the Vietnam War (hence the black and white imagery and 1960's font on parts of the images) that I will eventually finish for @37mm's awesome Heaven and Earth mod for CMSF2:
The above is the tactical map.
The above is the operational map (technically it isn't operational - but that is the image slot it has to fit into).
If you want my take on scenario design (including briefings and images), I did a tutorial on it here:
Note that this was for CMSF 1 so there are no tips on triggers or any of the new tools that came in with later versions of the engine (the same is true with the scenario design tutorial that bundles with the game) however the mechanics of about 80% of the current editor are the same as those for CMSF 1.