When a reef is the answer (and I've sailed on boats, inckuding a DS, that were rigged for three levels) here's the basic idea.
You need to have a new clew and a new tack grommet put into your sails, with proper reinforcements (called reef points). (The Basic Concept shows that schematically).
You need to mark your halyard so you know how much to let out so the main can drop to accommodate the bottom being reefed.
You need a line to pull the new clew down and aft, and that line is led forward, so you can operate it. On one side of the boom you put an eye, on the other side a cheek block. They aren't opposite of each other, you'll want one of them sitting further back to get the pull aft (so the new foot of your reefed sail can be flat).
In front you can rig a line going up and back down to bring down the new tack. Or you can hook the new tack into a hook at the gooseneck, and then tighten your halyard keeping the luff of your sail flat. Which system you use is a matter of taste.
There are many sources for suggested setups, or you do your own, based on these basic principles (what I did).
Initially, you'd put a reef in on shore to depower your rig in advance based on conditions.
The real challenge will be to do that while on the water. If you know how to heave to, you'll find that the easiest way to go. If not, read up on that and practice. (That's what I did).
There's really no particular magic "perfect" setup; a number of solutions can work well. It might also not necessarily be the first thing you add to your boat (that is, if you can reasonably forecast that your trip will not see gusts over 15).
I find that even solo, I can manage with gusts up to perhaps 2o, but if those gusts are frequent or particularly unpredictable in timing/direction, I usually don't find that as much fun and will head for a sheltered bay. But sustained winds around 1o are definitely not a problem; those are the sweet spot for the DS.