@Corucent It doesn’t go at the bottom of the header.liquid.
Option 1) Start at the top of the page in header.liquid, and scroll slowly down until you see the tag opener, paste the initial code provided directly under that tag. Save, then check for changes.
Option 2) Start at the top of the page in header.liquid, and scroll slowly down until you see the <%style%> tag opener, paste the initial code provided directly under that tag. Save, then check for changes.

