Building Dashboard by the data from other websites

My requirement is building a Dashboard for a user and showing the analytical part from the data getting through aggregators websites .

The aggregator website consists of functions like looking details of the order received , changing status of the order , etc .

If a user changes the order status it must get reflected the same in the aggregator website .
The concept is we have 4 aggregator website dashboard with login and each and every time to look after a new order we need to open the concern website .

We are trying to provide a single dashboard that connects all the other aggregator dashboard and perform the task .There are no API provided by the aggregator , parallely we need to capture and save the data received from aggregators and provide analytics for the data received .

Kindly guide me how to start this requirement .The industry for which I am making the product is Food