Sure, I’ll try my best to walk you through it. However, bear in mind I am no expert in Tasker either. I just followed some examples and did a lot of trial and error. I use 2 tasks in the Profile: a visual notification task (so I can tell if the event triggered) and the AutoCast task.
Best to use this example by SharpTools for an Event: Thing State as a guide for setting up SharpTools and Tasker. Here are some screenshots:
Tasker Profile
In the screenshot above for Thing State, you will want to enter the name of your “Thing.” The Attribute may be “contact” like mine or it could be something else depending on your Thing.
Tasker Tasks
Your variable in the If statements may be %st_attr_value or it may be something else, double check. Note: I am not 100% sure that the If statements are needed, but it is working as is so I’ll leave them in for now.
AutoCast
Cast Device = your Google Home name, select to set.
Under Screen, select Full Screen Media Screen, back, then go to Full Screen Media elements
Select Audio, then Audio (Song to Play) and select the audio file you want to use. Click OK, back and back.
Before you click the check mark, go to Advanced and select Wait For Result.
Go back, click check mark, click back, back and back to exit Tasker and save the Profile/Task(s).
Next test the action by opening and closing the contact. You should get a visual notification at least and hopefully a Google Home announcement. You can also monitor the logs under AutoCast to see if that part is working. If it fails, try rebooting your device and Google Home.