Hey HKB,
You can always reset your UI layout to default via Editor Preferences. Go to Edit > Editor Preferences > Miscellaneous and you’ll find a Reset UI Layout button. It will require a restart, so make sure you save everything first!
Where are you trying to dock windows to, exactly? You should be able to dock Content Browser by dragging it; you’ll see a white grid with sections you can dock it, or you can drag it into same window as another tab and make it a multi-tab window. Sometimes you have to fiddle around with position of a few windows to get it looking way you want, but it should work. Is it not working for you at all?
Hope that helps!