What ingredients do you need to dry food?

Depends on what you are drying.
When I dry onion tops, celery, bell peppers, etc, I just spread the chopped item on my racks and dry them. ( I use a great home made dehydrator )
If you want to dry things like strawberries, banana's, apricots, etc., you can rinse the fruit in lemon juice to preserve their color. I could care less if my apricots turn a little brown, so I do not bother.
How you store it after drying, is also a factor. Herbs I keep in jars in the pantry. Fruits I put in zip-locs in the freezer.
You have to consider how long you plan on keeping the dried food. If you are going to store it for a long time, use the lemon.
Drying is easy . . . Good Luck !