Rule: Start Action with Alexa Alarm

Well, I’m not writing it for you.

First, plan what you want to do.
That seems to be to run a rule every minute, and to see if the “alarm time” is past yet.
I think that is the wrong approach, but it will work.

So, create a rule that runs every minute.
Then find out how to use if() to compare “now” with a DateTime type item.
Remember not to see if it is equal - it never will be in milliseconds.
Test to see if now > alarm

Here’s a useful resource