For my seed starting mix I use 1 part potting soil to 2 parts peat moss (seed starting mix).
I use plastic cup filled 3/4 of the way with my seed starting mix.
Make sure before filling with soil you punch out 4 or 5 drainage holes in the bottom.
Place in your seeds and sprinkle with the correct depth of seed starting mix.
Use a spray bottle (recycle a old bottle- make sure anything you use is cleaned very well) and spray the tops of your cups until you can see the top is soaked. ( do this every 2-3 days until seeds are sprouted)
Place cups in a shallow tray and fill the tray with water about 2 inch deep. Make sure this stays full through the growing process your new cups will soak up the water from the bottom encouraging good root growth.