Rinse berries and remove any twigs, leaves, etc.
Check berries by either freezing for a few hours, poking each berry with a pin, needle or paperclip, or quickly blanching in hot water.
After you've checked your berries, spread them out on your dehydrating trays. Try to put berries of similar size on the same trays.
For sticky berries or fruit, I highly recommend the silicone mats for easy clean up. You want to the berries or fruit to be evenly spaced so they dehydrate at the same rate.
Turn on your dehydrator to 135 degrees Fahrenheit or the fruit setting if it has one.
Check your berries or fruit after 12 hours and rotate your trays. My top tray dehydrates a tad faster than the bottom one, especially when I've got all four stacked at once.
Even with checking, berries take quite a while to fully dehydrate. My cherries took 28 hours. My small blueberries were done at about 24 hours, where as the larger ones took 36 hours.
Your fruit is done when it's shriveled and slightly tacky/sticky. You don't want it to be rock hard but neither do you want it to have too much moisture that it could mold. A simple trick is to put a small test amount of still WARM fruit straight from the dehydrator in a sealed glass or plastic bag. If after a few minutes you see any condensation inside, put the fruit back and dehydrate longer.
Store dehydrated berries in an airtight container in a dark cool place for optimal shelf life. Use in homemade breads, muffins, granola, candy, or just plain old eating! Be warned, they're kind of addicting.