This is used when you want to make certain deals visible to non-admin users or when you want all relevant users to receive notifications about specific deal. In order to work properly, we advise you to first set User roles, setup Permission settings, and add users to Workflow. Also, user must be added in Workflow.
When adding new deal you have option to type in names of people you want to collaborate with you on that deal. In Deal details section among Deal Title, Deal Owner, Deal Value and other options, you will have field with tile "Choose team member(s)" in it you can type name of people you would like to collaborate with on the Deal.
Once finished, press "Save" changes to apply and you will see bellow deal owner team users that have been added to that Deal. These users will be able to access deal even if they don't have admin privileges and can be notified about deal updates (depending on their own Notification preferences in Settings > My Updates and Reminders).
When editing existing deal you can always go back to this step and add more team members if needed. Open Deal where you want to add them go to Deal Actions > Edit Deal and follow same steps as when adding new deal.