Start by telling us what county you are in. Although we all have the same Missouri statutes, different counties (and different judges within the same county) may do things somewhat differently.
Consider hiring an attorney who does lots of evictions for your first one. Watch and learn - and then do the next one yourself.
However, whether you hire an attorney or not you want to know the state statutes. If you click on the link for landlord/tenant state laws and Missouri near the top of this page, you will find the relevant chapters. However, the state page has changed somewhat, so you may need to use google or something similar to get to the state statutes.
There are two main ways to do an eviction - landlord's petition (rent and possession) or unlawful detainer. And if you want to get a money judgment, the tenant must be served. If you mainly want possession, you can do an extra form for post or serve. Posting is sufficient to get a judgment for possession.
This will just barely get you started.
Some counties provide the forms, and some don't. If you belong to a local landlords association, they may have the forms and/or someone who can mentor you.
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