Build a script to turn on and off VMs on Azure using power shell

I want to write a script in Azure Runbook (powershell) for the following scenario i have 2 VMs VMone and VMtwo, only 1 VM should be turned on at any given time, If VMone is tuned off, the VMtwo should turn on, if VMone comes back up VMtwo should turn off automatically. Each time a VM is turned on or off i should get an email / SMS notification apart from checking the VM status i would want to retrieve all the processes that are running in the VM if it is running (so that in the future i can turn on/off the services as necessary). And i want you to walk me though the script on Azure so that i can replicate the same on my account on a later date please.