How to become a substitute in Missouri?

I am stuck and cannot find any information on how to become a substitute in Missouri. Like an idiot, I paid for a certificate application through Dese because it listed it first as if you needed it before any 20 hr training. 🤦🏻‍♀️

Now, looking back, it suggests Kelly education which has NO information on their site, when you click on the Missouri training it just brings you to a payment page. That’s it. Nothing is breaking this down and I was hoping someone would have suggestions and steps please