You'll need to run a set of release clips from each kite. I use three clips on each kite line so I can fish three rods from each kite. Black's Marine Kite Release Clips are durable and easy to use. In order to use multiple clips on each kite line, you must drill a hole through each clip so the kite line can pass through it. Each of the three holes needs to be successively larger (the hole nearest the kite the smallest).
Then you need three stops, successively larger in size, in your kite line, one to stop each of the three clips from sliding back to the boat. These stops can be either swivels spliced into the line or floss or Dacron knotted around the line. Swivels are easiest to rig, especially thanks to the tiny high-strength swivels on the market. Floss takes longer to rig but won't corrode (though stainless-steel swivels hold up well).
If using swivels for clip stops, I would go with a very small Spro or Billfisher stainless-steel swivel. At the terminal end of your kite line, tie a snap swivel to which you'll attach the kite. Splice into the kite line 100 feet down from the kite (toward the boat) the first of three swivels, this one the smallest (a 70- or 80-pound swivel).
Another 75 feet down, splice in a second, slightly larger (100- to 120-pound) swivel. Be sure the hole drilled in the second clip for the kite line to pass through is large enough to allow it to slide over the first swivel when the entire kite line is cranked in.
Finally, another 75 feet down the line, splice the third and last swivel (200-pound or larger; this will be the closest to the boat). The swivel must be large enough to stop the third clip from sliding toward the boat but small enough to pass through the kite-rod guides when cranked in. The hole drilled into the third kite clip will be small enough to stop at the third (biggest) swivel but large enough so the first and second swivels will pass through it and it can join clips one and two to slide all the way to the kite when the kite line is cranked in.
In the event this sounds like too much hassle, no worries: Most local tackle stores can rig your kite line for you!
If you opt to try the waxed floss (or Dacron) route for kite-line clip stops, as do many pros in south Florida, follow pretty much the same drill, but instead of splicing in swivels, tie half hitches around the kite line with floss until the knot has sufficient bulk to stop a clip. Just as with the swivels, each knot (as one heads down the line from the kite toward the boat) must be bulkier and each clip drilled larger. You may want to secure the floss knots additionally with some glue. One advantage of using floss is that it creates a kite line that's intact, without splices.
With kite lines rigged and ready, it's time to deploy. But how many kites do you want up there? Many boats fly two at a time. That may sound intimidating, but it's really very simple if you force your kites to fly in a split that keeps them from tangling and also provides wider coverage.
To ensure this, attach a small split shot to one of the kites. If you want your kite to fly to the right, attach the shot to the bottom right corner. If one shot doesn't do the trick, add a second or even a third. Still not enough rightward pull? Rather than adding more weight, remove the shots and add one to the top right corner. Ditto on the left kite, so the two fly their separate ways. Every kite's a bit different; it all comes down to trial and error to get your kite flying perfectly. Once you get it right, leave the split shot on and label the kites as right and left.
One word of caution, though: Adding too much weight can keep your kites from flying high enough. The solution is a bridle. Each kite manufacturer offers instructions to adjust a bridle so you can force low-flyers to go high. But adjust the bridle only in small increments; large changes may make the kite spin out and end up a floater versus a flyer.
Inevitably, kites will occasionally do just that: fall into the water. Most kites sink, so if you're not quick on the retrieve, you will end up losing it. To avoid that costly scenario, I attach to the back of my kite a small balloon that functions as a life preserver. Some kiters place floats on the spars of their kites. If your kite does attempt to visit Davy Jones, retrieve it slowly. Even with floats or balloons, forcing a kite through the water at the wrong angle can snap kite spars or center pieces.