To do anchors you will need to edit in HTML, in the WYSIWYG click the HTML button to access:
This will bring up the HTML editor:
1) First you have to establish the target.
It must be a piece of text or image in a tag:
<p>, <span>, <div>, <h1,2,3..>, etc
In the HTML editor add id="[choose a unique name]" to the target's tag eg:
<p id="target1">Target</p>
Update the HTML editor
2) Create the link or button normally in the CMS
3) Modify the link or button to hit the target using the HTML editor
If it's on the same page, it will look like this:
<p class="button"><a href="#target1">Button</a></p>
If it's on a different page, it will look like this:
<p class="button"><a href="/link/6b2ce786866e45b8a29c5686825a191b.aspx#target1">Button</a></p>
Update the HTML editor
For more information on anchors see: https://www.w3schools.com/tags/tag_a.asp