to clarify or possibly simplify what others have said about the vermiculite-
I pour a bunch of vermiculite into a gallon bucket, and then pour a bunch of water into the bucket (I fill the bucket- exact amount is not important- saturating the vermiculite is the thing).
I grab a fistful of sopping wet vermiculite out of the bucket and sqeeze it as hard as I can until no more water drips out of it. I drop the fistful into plastic food storage container and repeat until the storage container is a little over half full.
I mostly use perlite rather than vermiculite, although I use both depending on what is available (In my area I have limited access to either product unless it has fertilizer in it, which I avoid). Personal preference- just keeps hatchlings cleaner and easier to see eggs during incubation.
For perlite- you can get a small gram scale and put equal weights perlite and water into your food storage container.