Sprint planning sessions are important events in Scrum. Valuable product increments are delivered to the client through properly planned sprints. The product owner, responsible for delivering the business value in the project, plans the sprint by selecting the most important product features (in the form of product backlog items) and presents them to the development team during the sprint planning meeting. The main objective of the product owner is to ensure that:
The sprint goal is properly defined
Acceptance criteria is clearly stated for each user story
Definition of Done "DoD" is properly understood by the team
While the product owner works out these important factors affecting the success of the sprint, the development team puts in its best efforts to understand the product vision and develop user stories in the best possible manner to fulfil the project goal.
The sprint planning meeting is actually carried out in two parts, with each part dedicated to a specific activity.
Two parts of the sprint planning meeting
The sprint planning event is attended by the product owner, scrum master, and the development team. At times, if they desire, stakeholders and/or management personnel may also attend the meeting after getting a permission from the PO. However, it is the product owner's discretion to decide if and how many of non-Scrum team members can attend the sprint planning event.
The first part of the event mainly concerns the PO as s/he explains the sprint vision and goal to the team. In the second part, the development team decomposes product backlog items, or user stories, into developable tasks for the daily sprint.
The first part
During the first part of the meeting, PO shares the sprint vision with the team, and presents the sprint backlog containing important PBIs for development purposes. PO explains to the team what the proposed increment plans to deliver in terms of business value to the client, and how should the team develop the stories. The functionality desired in product features are also explained to the team. Perhaps the most important task of PO during sprint planning events is to state and clarify the sprint goal in addition to the Definition of Done so the team can decide the development process and deliver potentially "shippable" product increments to the client.
The second part
In the second part of sprint planning event the team meets to discuss how the PBIs should be decomposed into developable tasks. Stories are broken down into simpler, and easy to develop functional entities which can be developed independently of each other. Once this is done, the team decides which of the developers should take up which tasks. In scrum, team members have to pick their own tasks, or select them through mutual agreement. Developers generally choose tasks depending upon their levels of expertise and skill sets. Experienced developers may take up more complex tasks, while less experienced ones might select simpler features or functionality.
The PO may, or may not attend this part of the event, but should remain available if needed. If the team faces any problems, or has confusion regarding any activity undertaken in the upcoming sprint, it can request the PO to provide the answers.