Open a dialog box on a click customised button

Hi, 

I'm working in CRM 2013 and I'm trying to open a dialog box from a customised button in Ribbon Workbench. This dialog box get some values from the Forms in the opportunity entity and the button should allow to update the status of the opportunity. 

I added a URL command to the button to open the dialog box and it works but just for one form and not for every single opportunity. 

I understood that it is because of the URL is just for one form, but I don't know how to do what I want that it's open the dialog box with the values from every different form. 

Maybe it just too simple but I'm really a beginner in this area. I'll be grateful if you can help me about it.