Installation, Setup and Usage - CrypticButter/ButteryTaskbar GitHub Wiki
Download and Install
Download the latest release of Buttery Taskbar and run the executable file. Make sure to download ButteryTaskbar-setup.exe and not the source code!
Note: If your anti-virus/anti-malware software (or SmartScreen, for that matter) complains about my application, tell it that it's wrong. (That is to say, allow Buttery Taskbar to install.) The application is not harmful or malicious. Furthermore, you can even view the source code and build the app yourself if you're that sceptical.
Configuring Windows
Make sure to set your taskbar to auto-hide. If you don't do this, you'll end up with a huge, unusable gap where the taskbar would have been. Auto-hide makes this gap tiny, allowing you to reclaim virtually all of your screen area.

You may also want to consider putting some of your notification tray icons in the overflow/hidden menu (including the Buttery Taskbar icon) for easier access to the context menus. Sometimes it can be a bit fiddly trying to access them from the taskbar directly when using Buttery Taskbar
Usage
You will need to use the Windows key to view the taskbar.
The application can be accessed by its icon in the notification area of the taskbar. In order to access the settings, right-click on the icon (secondary-click).

(Just so you know, the icon consists of a yellow arrow and reads "Buttery Taskbar" when hovering your cursor over it.)
Next, view this guide, so you can get an understanding of what the different settings do and why you'll want to use them.
If you don't have a mouse with programmable buttons, I recommend keeping one hand (preferably the right one) on your keyboard for executing shortcuts such as alt + tab or simply pressing the Windows key.
I've lost the application!
If the application isn't running (perhaps you've disabled the auto-startup feature or pressed "Quit"), search Windows for "Buttery Taskbar". This can be done in Windows 10 by pressing your Windows key, then subsequently typing your letters. Of course, if installed, you should see the Buttery Taskbar entry. Click that to run the application, hopefully causing the icon to appear in the tray.
Problems and feature requests can be reported in the issues tab.
For further empowerment, read the tips for making the most out of your Buttery Taskbar.