Welcome to ATP
and I do hope we can help you a bit here.
Of course you can plant out into the garden, Anita, but you'll have a lot less chance of germination and success doing that. Blazing sun, rain, drying winds, heat and cold of spring weather, birds and animals and slugs and insects eating the seedlings, all contribute to a low success rate of tiny plants and most perennial herbs start out pretty tiny! You have controlled conditions on your windowsill in the house to at least get the little plants up and growing. Some even take a very long time for the seeds to germinate in the first place, increasing the chance that some bird or squirrel will eat the seed.
Where are you located? Is the weather already really warm where you are? If not, get some seed starting mix and plant those seeds. If so, try planting some seeds out, but I'd start some indoors as a backup.
You can use plastic food containers, yogurt cups (with holes for drainage) or any small clean food containers work just fine. Don't use peat pots, though. They are not good for starting small plants and do not break down fast enough when you transplant for the plant to establish a root system.
I really like clear plastic containers with lids, as you can use them as a mini-greenhouse for your seedlings like so.
(the chopsticks hold the lids up a little for some air flow)
