You came to the right place for help.

Lets start with the rocks in the bottom bit. It does nothing but take up space. Forget you ever heard someone suggest it.

You can just put some potting soil in a pot and sprinkle seeds on top and then cover with a little more potting soil. Just use a good potting soil, not miracle groe. Thst is how most of us started out. You just have to be careful not to over wster.

You might want to read the container media thread. It has a lot of valuable information about how potting soil (it gets called container medium here a lot. We're fancy like that lol) actually functions in pots.

Different herbs need to be started at different times and under different conditions. Some are best bought as small plants that can be transplanted to your 8-inch pots, like oregano, rosemary, sage, and tarragon. Others can be started as seeds in small nursery pots under lights or in a sunny window and then potted up and taken outdoors after your last frost, like basil and marjoram. Some, like parsley and dill, grow long tap roots right away and don't like their roots disturbed, so they need to be started as seeds in deep containers. Most herbs do best grown outdoors in the summer in full sun. I suggest you do some research by googling the plants you want to grow to figure out the conditions they prefer.