An internal link is a link to another page or post on your own website.
For example, if you have written a review of Wealthy Affiliate, you may want to refer visitors to it from another of your posts, if that is relevant.
I order to do that, you first need to find the URL for that particular page or post.
Tp do this, click on your website title at the top of your published page or post, thus:
When you click on the website URL it will expand and become highlighted:
That expanded URL is the URL link for that particular page or post, and no other. Simply Copy it.
It is always a good idea to test it to make sure that it does in fact lead to the page or post you want.
You can then use that URL to link to where you want on your website using the method just shown. Or you can, as in the case of my questioner, put it in the review section of Kyle's lesson as he asked.
Prettify your Link
As you can see, the page URL link you have just found is rather long and far from pretty!
If you wish, you can tidy it up and make it look much better by making it into a Pretty Link. I am not going to explain how to do that here, as another member has done an excellent training on Pretty Link. Here is the link to it:
https://my.wealthyaffiliate.com/training/how-to-use-the-pretty-link-plugin/a_aid/dabd959f