existing website to manage

What's the URL to your current website?  Most static sites are no problem.  But a site built in WordPress or Blogger cannot be maintained in Dreamwever. 

First thing you are going to need to do is define your site and setup your connection to the remote server to grab your site so you can work on the files in DW. This article should help you out:

Define a site |

How to set up connection between Dreamweaver and the publishing server

[moved from Adobe Creative Cloud to Dreamweaver support forum]