To dry herbs is simple too. Gather the herb into a bunch. Tie the stems with a rubber band until they tightly secure. Tie a cooking string to the rubber band and hang it upside down on a wall or from the ceiling for a week (it’s different time for each herb, also depending on the humidity level in the air.) When the leaves are dried up, cut them with your hands (over a bowl) and store them in a container.
You can find rose petals and rose buds in Mediterranean groceries stores or Amazon (Eilat Market in Los Angeles has a big selection of dried herbs.)