What you're asking for doesn't mention a Trigger. A Flow cannot run without first defining the Trigger. With that said, the Planner Connector defines the actions that you can perform within Flow, and create and/or copy Create a bucket and Create a task.
So, in theory what you are seeking can be done - with the exception of the checkbox items, it would just depend on your Trigger, which would likely also be the source of the data for the title, description, dates, etc.
At this time, Flow cannot add or manipulate Planner checkbox items. If this is functionality you would like to see added to Flow or a Flow Template, please consider submitting it to the Flow Ideas page, where it can be voted on by other users, and tracked and commented on by the Flow team.
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