Wrong. You have three tenants. The lodger law only applies to an owner occupied residence with ONE lodger. When you allowed more to move in they ALL became tenants.
To do it legally you must follow the regular eviction process.
Go to the courthouse and get the paperwork you need. They likely have a packet put together. At the court the eviction process is referred to as an unlawful detainer.
There are plenty of resources available on the internet to help you learn the procedure as well.
Also, yes, you can give a 3 day notice demanding payment, but know that the notice has no legal effect toward eviction if you don't follow the correct process. You can always demand payment, you just can't legally force them out if they fail to pay.