That's easy:
1. Cop rings doorbell.
2. Occupant answers door.
3. Cop shows occupant the warrant, and says "I am Officer So-and-so, and this is a warrant to search the premises at this address".
4. Occupant reads warrant to confirm correct address.
5. Cop enters to execute search warrant.
That's not so hard now, is it?
You forgot #6. Bad guy sees cops at door and flushes contraband and down toilet while police wait outside.
I’m talking about a no-knock warrant. You’re in bed and you hear the cops kick your door in. They’ve got the wrong address. They entered illegally.