Layout file not applied

Hi,

Following the github instructions on editing the layout/creating a new layout, but I’m stuck for hours because my page simply doesn’t want to apply any edits from the _layouts folder.

These were the instructions I followed to change the theme’s HTML layout:

  1. Copy the original template from the theme’s repository
  2. Create a file called /_layouts/default.html in your site → lewinschmitt.github.io/default.html at 2237e6b3cfcf202430fae34cb885dbedb9a809e9 · lewinschmitt/lewinschmitt.github.io · GitHub
  3. Paste the default layout content copied in the first step
  4. Customize the layout as you’d like

So after struggling with this for a while, I included a simple paragraph in _layouts/default.html to see whether the layout would be applied successfully (so far without luck):

You can see the rendered page here: A test page | lewinschmitt.github.io

What am I doing wrong? Do I need to link to the layout somewhere else? Am I using the wrong directory for the default.html? Thanks for your help!