Feel each container almost full with the soil mixture. Keep in mind that it will compress as it gets watered. I recommend watering the soil prior to adding the seeds because it helps keep the seeds right where you want them.
For extremely small seeds (cabbage, tomatoes, etc.), I will carefully sprinkle them on top of the soil and then add more soil on top to cover them. For the larger seeds (pumpkin, zucchini, etc.) I will push them down vertically into the soil until the top of the seed is at least a half an inch below the top level of the soil.
Label each container with the plant name. I find that wooden popsicle sticks and a fine point sharpie work best.
Ensure the seeds are kept in a bright and warm location. They must remain moist to sprout, so water them daily.
Once there is more growth beyond the first set of leaves, the starts can be separated and replanted into a larger container, if needed, prior to planting into the ground or your raised beds.