Current system with more than 4 cameras

How do I add more cameras for complete plan?

Surety Complete allows you to use up to 4 ADC compatible cameras by default. If you need to use more cameras, then you can add the Extra Video Support add-on ($5/month/Level). Each level of this add-on supports 4 more cameras and 5000 more video recordings/month.

Add-ons are not purchased at the same time as the plan. They are added to your plan after account set up through your Surety Login. (System Manager)

Thank you for the detailed guidance.