Here's where the magic happens. To show you how it works, I used one of my older projects: Choose My Smoothie.
When you use Pastel, there are 2 modes: 1) Browse, and 2) Comment. When you're on the first mode, you can use the website like normal. In Browse mode, clicking on "All Smoothies" (on the header menu) would have taken me to the all-smoothies page.
The second mode, as the title hints, is Comment mode, where you can't exactly "interact" with elements. When on Comment mode, clicking on "All Smoothies" doesn't take me to the all-smoothies page, it creates a new comment. You can see this reflected by the number 1 on "All Smoothies", as well as the left sidebar that lists all comments I have made (for now, just one).
On a page with many comments, you could browse through the list of comments on the left sidebar, click on each comment to open up more details (what page the comment was on, if there are replies to that comment, and the option to mark a comment as "resolved").