I extracted the file and added all the folders into the addons folder.
What am I missing? Here is a screenshot of addons that is in:
https://imgur.com/a/OpkdFTL

GUI and default skins are both missing and both required.

Where can I find them to download and add to the addons folder? (Odd as this is the 2nd time I downloaded this and never had an issue before.)

they're already included in zip on any of trusted download sites like curse/twitch and WowInterface. If you are downloading from somewhere else, it's not recommended.

I am pretty sure I downloaded it from curse like I normally do.

Yep, it was from Curse and I hit the download button that is at the top right hand side of the DBM page.

Ok I redownloaded and looks to have more files then my last download, very odd. Hopefully will work now!