There are several ways to open the the actual SSIS package (the dtsx file).
One way is to open Visual Studio, create a new SSIS project and then, in the Solutions Explorer, right-click on 'SSIS Packages' and select 'Add Existing Package'. from this dialog you can select the Server and then the package you want to import.
If i implement this method will it in any way effect the live package on the server . ie if I where to play around with the package on my local laptop after exporting will it effect things live - does the live package still remain 'as is' on the live server ?