I think u means by Hidden is a sub category. 
One thing to Note If you paste a website main index page or home page link
then HTTrack will go through it tep by step. But the problem is Robots.text
issues, some web owners secured their web site from being scrapped and
mirrored. 
So i think your problem is that one, like you paste some page link and it
download only that page and not the sub catagory page content.
For this you need to either paste the home page or index link to download the
whole web site or you should just paste all the links of pages that u want to
be downloaded.

 For example: I want download the two pages from any category of this
website.
www.pakmcqs.com
For example I want only two pages from Category EVERYDAY SCIENCE. So i will
just paste these two links.
<https://pakmcqs.com/category/everyday-science-mcqs/page/1>
<https://pakmcqs.com/category/everyday-science-mcqs/page/2>

Hope its helpful for you.

For more help just watch the video about..
<https://www.youtube.com/watch?v=RC10BBBFF6E>