First, go to the Galaxy Store and install Good Lock. Additionally install all the components.
Open NavStar. Turn on and select "New configuration"
The Background Colors are way too light for me so I don't mess with that. You can use Navbar App to select colors if you want. Now select Button Layout
Check the layout you prefer and then click "Icons".
On a different subject I wanted to point here, if you select "Add Button", you can add an additional button or two to your navbar. When you add button, it takes you to another screen where you can add camera, screen capture, internet, etc. and you can theme those too.
Select the icon you want to modify. In my example, I chose Home. Here you can select one of the icons that came up or on the bottom select "More Icons".
Complete action using.....choose where the icons you're going to use are located.
Go to the folder where your icon is and select it. Turn OFF Adaptive icon colors. If you have more icons to build, repeat the steps for each one here so when done, all the icons will show. Then SAVE
Once you save it takes you back to the New configuration screen. Scroll down and select the set you just created.
And now you are done
Please let me know if you need additional help :)