I have an adult daughter living with me and her two teenage children. How can I get them out of my home

Yes you can, and maybe suggest alternatives for them, but if they don't go willingly, the will go forcefully through the laws of eviction in your own state or county.

Yes, you evict them just like you evict anyone. Have you discussed this with them,

ANYONE living in your home who is not an owner can be told to vacate by the owner(s). If they refuse then the owner(s) need to obtain an eviction order from the courts.