Call around to your garden centers right now and see if anyone has agastache to sell. Even one plant will get you stated nicely...it will bloom soon and then will seed all around itself. You can also spread the seed where you want it. I carry the stalks around my meadow and shake them as I walk.
I'll check some suppliers I use for seed and post the info.
As far as planting the seed, there are no special needs other than some open soil, a light cover of soil on top of the seeds, and water till the seedlings take off. They don't need coddling. Hope this helps.
Buy locally, buy only humanely raised animals, eat in season, keep bees!