The basic set-up is a wire mesh screen (a clean old window screen will work fine) that allows adequate air circulation, set in direct sunlight and covered with sliced tomatoes, and left alone until the tomatoes are dry and leathery. Sun-drying is pretty easy, but details of your set-up and effectiveness will depend on a number of things. I've tried to give a list below.Type of tomatoesRoma tomatoes are going to start out with much less liquid (less seeds/jelly and more solid flesh) than a big old heirloom variety, and thus be easier to dry. That's why you mostly see dried Romas at the supermarket. The standard is to cut them in half from top to bottom; obviously bigger tomatoes will need more sectioning, and thicker slices take longer to dry. You can remove the seeds/jelly from your tomatoes and just dry the pith if you prefer - try it and see what works best for you.Temperature and humidityHow dry and sunny is the area in which you live? If you're in a sunny spot in the Arizona desert, sun-drying will be a snap. If you're in a cooler or wetter area, you'll have to be more careful. Pick a particularly warm and sunny day (two or three in a row, preferably) and keep an eye out for rain; if it's humid, be sure your tomatoes are always in good sun even if you have to move them throughout the day; choose tomatoes that start out drier (see above); and be prepared to finish your tomatoes in a low (~150F) oven or a dehydrator if the weather doesn't cooperate.CrittersIf you have pets, or problems with wild animals or flies, consider making a double-layer of screens to keep them out of your drying fruit. A basic set-up could be two old screens held together with clamps; a more complicated set-up could be a hinged box with screening on both sides.How long you let them dry depends on the tomato type, thickness of slice, amount of sun, and humidity. I can't give you a specific time - it may take a couple of days. Don't forget to check your tomatoes once or twice a day, flipping them over and inspecting for mold (in cool/wet climates). Don't pack your tomatoes too close together on the screens, as you want them to have plenty of space for air to circulate. You can also blanch or sulfur tomatoes, but I've found this to be unnecessary extra work that prevents me from actually bothering to dry the tomatoes!If you do find sun-drying to be a pain for any of the above reasons, you can always try roasting the tomatoes. That's what I do with those big juicy heirloom types, since they just don't taste as good when sun-dried.Does that answer all of your questions?