Ideally you want whole leaves, as opposed to flaky salvia extract, it's just easier to keep in your mouth. I would take a good half a tablespoon of your extract, hydrate it in minimal water for 10-20 minutes, and start holding it in your mouth. You're not really gonna be able to chew it, and it's gonna be pretty uncomfortable with all the little particles getting stuck to your mouth, at least that was my experience trying it.
Tea is rather inefficient, iirc. The moment you swallow, it becomes ineffective, so you want to hold it in your mouth for as long as possible.
They say to brush your mouth and gums with a toothbrush prior to chewing to increase absorption.
Good luck!