Hi Barra! Let me give you a few suggestions as to how best to proceed as you dip your toe (but hopefully not your whole body!).
Sailing your Hobie ain't that hard but it is challenging and engaging to master, It is also motive power for FREE which is a great concept on your otherwise human powered craft!
Firstly, dig around on this forum to find the several posts about how to set up your kayak for sailing. Basically my recommendations are always the same: larger rudder, longer sheet (the rope that pulls in/lets out the sail) and 2 turning blocks (pulleys around which the rope turns) to reduce friction in the sheet when you are sailing so that the sail can be depowered in an instant and so that the sheet can be led to your hand from the RHS in front of the seating position rather than to your hand from behind the sheeting position.
You might also like to work out a way of stowing the rolled up sail on the deck of the boat when you are not sailing - I have a bungee loop tied round one of the forward hatch closure bungees on one or other side of my boat and a bit of line with a small snaphook in the end tied to the padeye on the gunwale immediately behind the seat on the same side. When you want to stow the sail lift the mast out of the mast base, lay it across your lap & roll it up, secure the roll up using a knotted rope (one end tied to the clew) crooked in the hook near the clew of the sail then poke the FOOT (NB not the head!) of the mast into the forward bungee and secure the rolled up mast & sail by lifting the snaphook behind you (with its line attached) over the rollup and snapping the hook onto one of the luggage retaining bungees. Deploying the sail involves the reverse procedure. T'ain't hard though you may have to 'hotch' yourself forward in your seat to access the mast base unless you have the arms of an orang utan. Now you can pretty much leave your sail rolled up but ready to use on your boat any time that you are not car topping it.
When you have led your sheet through the 2 micro turning-blocks that you have bought from your local Harken or Ronstan supplier (i.e. you need proper sailing ones, not hardware store ones) make sure you tie a stopper knot in the end of the sheet so that it can't back out of the block in the cockpit - a double overhand knot works fine.
Now to actually get sailing I suggest a couple of things:
1. beg, borrow or buy a basic manual on how to sail a dinghy - you need to understand the relatioship between 3 things: direction of wind; direction of travel; trim of sail. You can get the basic idea from reading a book and you need to do that but to become instinctively wind-wise you actually need to get out on the water and probably get a bit wet too!
2. choose a good day for your first attempts by which I mean a) light winds (you can only sail these winds in light winds so I recommend that you don't take your first steps in any kind of strong or gusty breeze)... the rule is the lighter the better as long as there is some wind rippling the water surface - if there's no wind your sail will just hang limply and you will stay still; b) warm water - just in case
3. I suggest making sure there's help relatively nearby just in case it should be required and that someone is watching out for you.
4. Secure EVERYTHING on the boat to the boat before you set off just in case you take a tumble - the last thing you want is to suddenly find yourself in the water beside your boat with your mirage drive, glasses and mobile phone disappearing into the murky depths. If it ain't tied on you can expect to lose it !
5. Before you start it might be a good idea to check that you will be able to right your boat and get back on board (even with the mast and sail up) in the event that you do go over !
OK now here we go: you have tried to understand your sailing manual (check); you have tied everything down (check); weather good & help at hand (check); wearing PFD and suitable clothing (check); sail rolled up beside you on the boat (check); sheet tied to sail, led through blocks and the working end has a stopper knot in it so that it will be always to hand in the cockpit (check).
Pedal out to where the light breeze is rippling the water.
Now turn the boat head to wind (to do this pedal forwards and turn the boat so that the bow is pointing directly into the wind).
Take the rolled up sail and deploy it - hotch forwards in your seat so that you can reach the mast base in the boat - undo the retaining rope from the clew hook on the sail, point the mast head to the sky and drop the mast foot into the mast base, unroll the sail from the mast by pulling the sail out horizontally by the clew, hook the securing bungee at the tack (foot) of the sail over the securing hook below the mast base on the boat. If you have done this quickly enough the boat will still be pointing head to wind and the sail will be flapping loosely more or less over your head. Regain your seat.
Put your feet on the pedals, pick up the sheet in one hand (right) and put the other hand on the tiller (left) now pedal forwards gently and turn the boat to point more or less at right angles to the wind in whichever direction you choose to sail. The wind blowing across the sail will make it fall away to the leeward side of the boat as you turn.
Now press one foot across both pedal shafts so that the pedals line up (the fins are now acting as a keel under the water) then gently pull in the sheet - the breeze will fill the sail and the boat will start to move forwards more or less at right angles to the wind (there is no noise and you may need to look around to detect the forward motion). You don't need to pull the sheet in far - just a hands width will do. Hold the direction you have chosen via the tiller - at this stage don't try to get too fancy - just go forwards a way at 90 degrees to the wind.
If the wind threatens to tip you over, let go of the sheet so that the sail depowers.
When you want to turn around to go back let go of the sheet, pedal up into the wind again and continue through the wind 'til the sail falls away to the other side and your starting point is in front of you and the wind coming over the side of the boat at more or less 90 degrees. Pull the sail in gently via the sheet. The wind will fill the sail from the other side and push you back the way you came.
Once you have done the above you are a sailor. As you develop your skills you will learn how to sail upwind, downwind, run before the wind, tack, gybe, etc but basically that's it.
You need to learn some sailing knots (bowline, simple simon, buntline hitch, double overhand stopper are my basic set for setting up you Hobie) and some sailing terminology (I have used sheet, clew, tack, block, padeye, tack, gybe, leeward/windward etc etc - most of these will be explained in your sailing manual if not try http://www.dictionary.com
Hope this helps and I hope you have fun!