
Explanation:

Box 1: Lead time
Lead time measures the total time elapsed from the creation of work items to their completion.
Box 2: Cycle time
Cycle time measures the time it takes for your team to complete work items once they begin actively working onthem.
Box 3: Burndown
Burndown charts focus on remaining work within a specific time period.
References:
https://docs.microsoft.com/en-us/azure/devops/report/dashboards/velocity-guidance?view=vsts
https://docs.microsoft.com/en-us/azure/devops/report/dashboards/cycle-time-and-lead-time?view=vsts
https://docs.microsoft.com/en-us/azure/devops/report/dashboards/configure-burndown-burnup-widgets?
view=vsts