Split Topics that are lengthy due to more posts

On Slackware forums, lengthy topics are seen as pages, with each page containing about 15 posts…this would help readers to read topics with more number of posts. Else, scrolling is difficult, we will not know where we left…

Unfortunately, this is how the forums software we use, Discourse, is designed - I don’t think we can enable pagination as you’ve described, as scrolling like this is one of Discourse’s signature features: Discourse features | Discourse - Civilized Discussion

I do note though that Discourse does save your scrolling position, so if you scroll partway through a topic, go to the forum index, and come back again you’ll be right where you left off.