The number of Pods are the amount of Pods working in a specific activity, in a single Pod station. Make sure that you have enough Pods for the activity and/or Pod stations you need. If you have more than the number of Pods required, make sure to set up the activity using only the indicated Pods that will light up accordingly.
To find out more on how to use the BlazePod settings, follow this link to the BlazePod manual.