help with photoshop workspace background change

[SS13]

I am new to photoshop and I am not sure if referring to my 'workspace' is the correct word. What I see when I open up photoshop used to be all dark grey and now its white...that dosnt worry me, but the configuration has changed and when I have more than one file open at a time I can only see one file, also when I press file, new, to create a new size template, that has all changed...I just want to get it back to how it was as I cannot navigate this new one effectively!

[Dave Merchant]

Change the user interface brightness using Edit > Preferences > Color Theme.

[D Fosse]

I think the OP refers to tabbed view. This is also changed in Preferences. Uncheck "open documents as tabs" to get the old behavior.

There is also a setting to use "legacy" New File dialog or something (not at my workstation right now so don't recall exact wording).