Before the sprint starts decide who is going to take on the key roles during the sprint.
Why should we do this exercise?
There are some important roles to be played during a sprint, not clearly defining who these people are could lead to discussions de-railing, desicions descending into long conversations, and failing to record an important detail.
Take some time to assign the following roles:
Leads the design sprint. The facilitator makes sure that the rest of the team understand the exercises and keeps to the schedule. The facilitator can answer questions that the team have.
Takes notes. The note-taker is in charge of the documentation for the sprint. They may also be asked to help setup timers, and collect votes, and oterhwise keep things organised so that the facilitator is free to lead the sprint.
Typically the client and the person with the initial product vision. This person has final say on any tough decisions. They usually have the broadest understanding of the problem to be solved
Once you have decided who these people will be send a message to the team to list the roles and who has been assigned them. If the team are not familiar with the people use this as an oppurtunity to informally introduce them before you all meet up.