If they are waves I would start them right now. they're slow to get going, but do well once they are growing. I'm sure there's lots of ways to start the seeds, this is what I do that has worked very well:
Use potting mix (not soil) that you can get at any commercial place that sells garden supplies.
I use starting trays, fill about 3/4 full and totally saturate, just no standing water! Sow seeds by just placing on top of soil and patting to make sure they are in good contact. Don't cover.
Mine just stay on the kitchen counter, no extra light, no sun, until they germinate. They will be tiny and delicate at first.
Then the tray goes under grow lights kept about 2-4" above the tray. water with a light mist/sprinkler so as not to smash them.
When first two true leaves show up and are a decent size, transplant into cells ( I use the 48 cell insert for them) to let them grow. AT this point they go to greenhouse, but would do fine under grow lights. Once well established, make up your hanging baskets.
One thing on wave baskets, can't let them ever totally dehydrate or they won't recover.
Hope this wasn't tmi. Have fun!