Hi madhu,
When you want your business object to work on an application,the application need to be connected with the Blue Prism. Attach will create that connection between application and business object.
Generally when you launch an application,the application automatically connects with the blue prism and when you try to attach this application again it throws an error saying it was already connected.
And when you are working on one application and if it redirects to another window then you need to attach that window to work on it.
