First wash the peppers and then put on a pair of gloves. Jalapeno juice burns and don't make the mistake of wiping your eyes if you have touched a pepper. Now cut of the stem end of the pepper. If you are cutting the peppers lengthwise, just cut into two large pieces or if you are cutting into thin slices, cut off the other end too, and slice into small slices.
Now place them on a dehydrator tray.
Turn on the dehydrator to 135 degrees and dehydrate for about 10 hours. Store the dried peppers in a sealed mason jar. I have kept them for up to a year with no problems.
To use, soak the dried peppers in hot water until they are soft (about 10 minutes). Then you can use them as you would a fresh pepper.