Sprint Planning Meeting
The Sprint Planning Meeting is attended by the Product Owner, Scrum Master, the entire Scrum Team, and any interested and appropriate management or customer representatives.

During the sprint planning meeting the product owner describes the highest priority features to the team. The team asks enough questions during this meeting so that they can go off after the meeting and determine which tasks they will move from the product backlog to the sprint backlog.

The product owner doesn't have to describe every item being tracked on the product backlog. Depending on the size of the backlog and the speed of the team it may be sufficient to describe only the high priority items, saving the discussion of lower priority items for the next sprint planning meeting. Typically, the Scrum team will provide guidance when they start to get further into the backlog list than they know could be done in the next sprint.

Collectively, the Scrum team and the product owner define a sprint goal, which is a short description of what the sprint will attempt to achieve. The success of the sprint will later be assessed during the Sprint Review Meeting against the sprint goal, rather than against each specific item selected from the product backlog.

After the sprint planning meeting, the Scrum team meets separately to discuss what they heard and decide how much they can commit to during the coming sprint. In some cases there will be negotiation with the product owner but it will always be up to the team to determine how much they can commit to completing.

We would like to suggest you the following list of usefull resources on the topic: