So many things here.
Firstly, I think this might actually be a good situation. You're learning about the eviction process, tenant screening (never "word of mouth" again), the power of a lease WHEN not IF a neutral third party needs to be involved, tenant/landlord laws, and managing tenants who don't care about your business the way you do. By the end of this you'll know more than a double-digit percentage of landlords.
Here is the order I would follow:
1. Go to bard.google.com and ask this LLM for tenant legal codes, articles, sections, and laws for evicting tenants in your city and state. Read those relevant parts and figure out how far in advance you must give eviction notice, how to handle evictions with no lease, etc.
2. Be ready and willing to change locks and give remaining tenants a key
3. Start doing showings for their room so they get the idea that they're evicted
4. After a grace period of 1.5 days give another notice and mention legal action or law enforcement
5. Pack their items, change front door locks and give new locks to other tenants. Call cops if they keep returning.