HOW TO STORYBOARD
Don't get too hung up on your ability to draw - it's cool if you can, but completely irrelevant if you can't. The storyboard is a planning document, not a work of art. (Unless you're a professional storyboard artist, in which case they are often beautiful.)
So, what is it we are actually planning? Have a look at this extract from The Mummy and pay attention to the storyboard; what are they actually planning? They plan (or they SHOULD plan) THREE THINGS.
VISION - the shot. The angle, the distance, teh composition, the lighting, the palette, position of people and objects - basically,arrange your mise-en-scene.
ACTION - The movement. Is the camera moving? Are the actors moving? Even lights might move. This also includes any notes about editing, transitions and so on.
SOUND - What sound goes with this particular frame. (Usually, there is a particular bit of dialogue that needs to happen when a certain thing is on screen. You don't need to write out all the dialogue though.
HOW MUCH STORYBOARDING?
As a basic rule, the more detailed your storyboard is, the better your film is. This is when you make all the creative visual decisions, after all. But you don't need to plan every single shot. If you know something is a simple shot-reverse shot, for example, then maybe you can just jot down a written note. Here's an example:
(the start of)
So this students (who was pretty experienced by this point) did not plan every shot; but she DID plan things that needs planning (like the dolly zoom when teh glass is dropped.)
BUT I CAN'T DRAW!
Oh, quit whining. Neither can we. Watch this for reassurance.
We learn to storyboard through reverse engineering existing shots. Here's a very short film. Choose a shot (or a sequence of 3 or 4) which seems okay to you and storyboard it in as much detail as possible.
A LITTLE MORE AMBITIOUS
There are other ways to plan shots and sometimes we need to use BLOCKING DIAGRAMS especially for longer, more complicated shots which incorporate multiple movements and shots. Look at the opening shot of this film; it would have been planned with a blocking diagram rather like this.
Basically, we need to indicate where the camera is (and there will sometimes be more than one), where the actors are and where everything is moving from and to. We also note key props and maybe even lights and other things which need to be kept out of shot. Students working at his level will almost always get the top grade, by the way.
And if you ARE doing long, complicated shots like this; you need to rehearse them. See below for the behind-the-scenes of teh famous opening shot of La La Land.
Storyboards are important in Media, and how you present them is always going to determine your grade. Make them clear and detailed and precise. Take pride in them. If you can draw well, then do! There is a template attached here; use it if you want find your own, or use blank paper. IT's also perfectly fine, and vastly quicker, to use photos instead.