You'll need your system patched with UX Theme Patcher.

Ultra UX Theme Patcher:
https://www.syssel.net/hoefs/software_uxtheme.php?lang=en

You'll also need 'Start Is Back' to apply the start menu & taskbar style & 'Old New Explorer' for windows explorer to look exactly like it is in the screenshot.

Start Is Back:
http://startisback.com/

Old New Explorer:
http://www.msfn.org/board/topic/170375-oldnewexplorer-118/

Installation:
a.Extract the contents of the theme folder & copy them to:
C:\Windows\Resources\Themes
b.From Personalization, select & apply the theme.

Important:
If you want the start menu & taskbar to look like it does in the screenshots then check the 'Start is Back Settings' folder for screenshots of settings in SiB 
specific to this theme.

This theme has a lot of transparency so for it to look the way it should you will need to use Aero Glass for Windows 10.

Aero Glass GUI:
https://mega.nz/file/jIhEyawA#UUX_cONrRgYv_LpY7v2gq1ab6wMuGDebvT0C3XpXm4w

This is the free version of Aero Glass with a GUI included for easy configuration. THIS WILL LEAVE A AERO GLASS WATERMARK ON YOUR DESKTOP WHEN IT IS ACTIVE.
Extract the AeroGlass folder to the root of your system drive & run the AeroGlassGUI.exe file inside as aadministrator. The settings for the program are included
in screenshots inside Aero GLass GUI Settings folder.

Disable new addressbar & searchbox feature of Windows 10 1909:
Windows 10 1909 aka 19H2 features an addressbar & searchbox which is wider than any before. To restore the old searchbox & addressbar, from the 
'Disbale Enable 1909 New Search' folder, run the 'Disable New Search.cmd' file to disable & alternatively run the 'Enable New Search.cmd' file as administrator to 
re-enable the new addressbar & searchbox.
Big thanks to Mr GRiM @ Virtual Customs for sharing these.

Extras:
Lockscreens @ 1920x1080 & 2560x1440 resolutions.

Bugfix:
Getting rid of white areas in themes after coming out of lock or sleep in Windows 10
Windows 10 loads theme color defaults from:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\DefaultColors] after every lock/sleep/hibernate.

Hence any time you put your pc to sleep/ hibernate or use Ctrl+Alt+Del to go to the lock screen & then resume back to windows,
certain areas of task manager & other windows turn white while using custom dark themes

Fix:
Open regedit & navigate to
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\
Under themes you'll find a folder/registry key called: 'DefaultColors'
Make a backup of that key, take ownership of it, and then delete that whole key.
The bug should be fixed now.

Enjoy.

D@rkside Of Aquarius