When you are creating your projects make sure you add all the stakeholders that are associated with the project. If you do this then they will be at the top of the list within the project stakeholders section when you are planning meetings and choosing attendees. This just makes it faster to add attendees to meetings that you plan. Otherwise you have to scroll or search in order to add attendees.

When you are creating a project select all of the Project Stakeholders that will have some affiliation with the project. These are individuals that will either attend meetings or will be subscribers to the outcome of meetings.
Now when you go to create and plan meetings the list of project stakeholders will show up at the very top of the stakeholder list when selecting meeting attendees and meeting subscribers.