Product Backlog creation in Scrum

Does that mean we usually have a separate meeting/session before the first sprint to create the initial product backlog or is that also part of Sprint Planning for first Sprint?

Give preference to the second option you describe as far as is practicably possible.

In Scrum we try not to put the establishment of empirical process control, nor the delivery of stakeholder value, in unnecessary delay.

Thanks Ian.

Creation of the initial backlog needs to happen before the first sprint so I have learnt that some folks have invented the concept of Sprint 0 to handle this along with many other mobilization activities. For example, we'll have a Sprint 0 that is inclusive of any trainings, sharing vision, journey mapping, experience plan, story mapping, hydrating the backlog. Then Sprint 1 will feed from that backlog. However, Sprint 0 is not in alignment of Scrum framework.

So, how is the requirement gathering (where user stories are captured) conducted in Sprint Planning? Would an 8 hour meeting (for a month long Sprint) be enough to capture enough user stories to create initial product backlog to start Sprint 1? At the beginning, there has to be a workshop session where the stakeholder put forward their wish-list (requirements) in the form of user stories, that would be prioritized & put into the product backlog.

Looks like a gap that different organizations are filling by using Sprint 0.

I am not well versed with DAD yet, so maybe the "Inception" phase covers that gap. Not sure though.

Scrum is not a complete life cycle methodology. It's a framework. As such, it doesn't address all of the different activities that are necessary to bring a product or service from that initial inception to retirement.

I don't think it's unreasonable to have some kind of inception activities for a new product or service. You need to form the team, identify an initial scope or boundaries, choose the process framework and methods, align with stakeholders, ensure appropriate funding, and other early types of work that, if not done, will prevent you from executing other work.

Before you even create the Product Backlog, you need to determine if you will have a Product Backlog. Assuming that you will, though, the initial scope definition will help identify what should go into the backlog. Forming the team also enables you to start refinement of the items.

Frameworks such as Disciplined Agile do define an Inception activity. With DA, you can use Scrum for the Construction and Transition activities and perform them iteratively. I don't see how you can effectively launch an effort without some kind of inception type work before your first Sprint. The idea should be to keep this as short as possible, doing what is absolutely necessary to set your team up for success.