You can apply two types of resource calendar: one based on people and one based on equipment. For example, during planning for HR, you will want to develop an output, which in one sense is really a schedule. This resource calendar projects your team's availability. Maybe someone is getting married or going on vacation or is unavailable due to other reasons. The other set of resources called equipment include materials that you need but are in demand throughout the organization such as conference rooms, special equipment, tools, or vehicles. The list is endless. You'll want to have a schedule of that equipment's availability so it is not overbooked.