ARP poisoning is achieved in _____ steps

The hacker begins by sending a malicious ARP "reply" (for which there was no previous request) to your router, associating his computer's MAC address with your IP Address. Now your router thinks the hacker's computer is your computer. Next, the hacker sends a malicious ARP reply to your computer, associating his MAC Address with the routers IP Address. Now your machine thinks the hacker's computer is your router. The hacker has now used ARP poisoning to accomplish a MitM attack.