I just use a good, fast-draining potting mix to start seeds, but I'm sure you'll get many different answers to your question about that. I thoroughly moisten the potting mix first, and after I've planted the seeds, I use a spray bottle to keep the soil moist. You don't want the soil to be too wet, though. If you can provide good air circulation, it can help avoid problems like damping off, which is caused by a fungus. When the seedlings are a couple of inches tall, I transplant each one into its own container, using the same type of potting mix.
As for the kinds of herbs to grow, I can tell you that lavender, while it is possible
to grow it in a container, much prefers to grow directly in the ground. Also, lavender seed takes quite a long time to sprout, so I wouldn't recommend it for a beginner's first effort.
Your location, and the growing conditions (light intensity, day and night temperatures, and humidity) you can offer will play a strong role in determining the types of herbs that might do well for you. I have always found it easy to grow basil, chives, rosemary and thyme. You might want to consider one or more of those. Oregano might be easy, as well, but I haven't ever grown it in a container.
"Isn't it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?" - Douglas Adams