Ask HN: Advice for Transitioning to a Product Owner

Hi, My spouse is transitioning from the role of a technical manager to the role of product owner within the same company. He is moving to a recently acquired unfamiliar new product though.

He has observed a few product owners on the job. This is the first time he is assuming the actual responsibilities. Since I hang out here often, I am asking on his behalf. What should the first steps be? What should he look out for? What kind of systems have been helpful to you to manage the load and the enormous amount of communication involved?

How do you track inputs from sales engineers, support, customer success teams?

What are the parameters you use for prioritization?