A building management system (BMS) is a computer-based control system that is designed to monitor and manage various building systems, including HVAC (heating, ventilation, and air conditioning), lighting, security, and other equipment. Here are some important elements to consider when building a BMS:

1. System Integration: Ensure that the BMS can integrate with all the different building systems, including HVAC, lighting, security, and other equipment.
2. Sensors: Install sensors throughout the building to monitor various conditions such as temperature, humidity, and occupancy levels. These sensors will provide data to the BMS, which will then adjust the building systems accordingly.
3. User Interface: Develop a user-friendly interface for building managers to easily access and control the various building systems. This interface can be web-based, mobile-based, or both.
4. Alarm and Notification System: The BMS should be equipped with an alarm and notification system that alerts building managers to any issues or anomalies in the building systems.
5. Remote Access: Provide remote access to the BMS so that building managers can monitor and control the building systems from anywhere at any time.
6. Energy Management: Incorporate energy management features into the BMS to optimize energy consumption and reduce costs.
7. Maintenance Management: Develop a maintenance management system within the BMS to track and schedule maintenance tasks for all building systems.
8. Data Security: Ensure that the BMS has robust security features to protect against cyber attacks and unauthorized access.

By incorporating these elements into a building management system, building managers can optimize building performance, reduce energy costs, and improve occupant comfort and safety.