As far as I can see, I think you’ll just need to copy and paste the HTML snippets. Details below.
WYSIWYG =
1. Click on the page to insert an insertion point.
2. From the page navigation bar buttons, choose the Source Code (<> HTML) button.
3. For the default (red) button, copy and past the code block below:
<p>Text for button</p>
4. For the White button, copy and paste the code below:
<p>Button white</p>
5. Choose the Apply changes button.
6. Save the page, and choose the Preview button.
Block Editor =
1. Choose the + icon to add something.
2. Choose the HTML icon from the floating icon bar.
3. For the default (red) button, copy and past the code block below:
<p>Text for button</p>
4. Choose the + icon
5. Choose the HTML icon.
6. For the White button, copy and paste the code below:
<p>Button white</p>
7. Save the page, and choose the Preview button.