Not sure I understand the question, but extension manager
that comes with your software will install the mxp extensions
automatically for you. Simply double click the extension, and
follow the prompts. They will be available in dreamweaver on your
next restart of the application.
If the extensions isn't compat with the version of
dreamweaver you are using, then you will need to find an extension
that will. You can always upgrade if needed, but not a cheap
solution just to have an extension work.