Lol, it’s REALLY easy. Go to Customize > Theme (where it shows all your HTML codes and whatnot) and you’re going to see a long list of things that say <meta name=“ blah blah blah” content=“blah blah”/>, so you’re going to want to paste THESE two codelines somewhere in inbetween the <meta name=“ lines, it doesn’t matter where really.
After that you have to paste THIS code into your theme, past all the meta name codelines, under <style type="text/css”> in your theme. It may not say text/css but just paste it under the style type tag. If something’s already under the style type tag then paste it under that. This is the base of your scrollbar.
Then go to your appearance tab (Still on customize), and check the Custom Scrollbar option.
Then, still on appearance, select your scrollbar color.
Whatever color you choose, it should appear:
obviously instead of this scrollbar:
That’s it! Hit save & you’re done. If this doesn’t work for you, you must have a different styled theme, something is different, etc. etc. and this obviously isn’t the right scrollbar tutorial for you.