Me and my colleague are working on a dashboard.
For example, he is developing some part of the dashboard as well as I am developing some part of same dashboard in my system.
Can someone please help how to merge these two into third system along with the design.
It is not a raccomanded way to develop, one must develop data access another one must develop interface.
In your situation the only thing to do is copy objects from one document to the other (if script and data are the same in both source document)