When you type something in the "Instructions for students" box of your assignment, it will look like this:
O.K., I thought, but how do the students see that? The answer is that they see it twice. First, it is on the opening page.
That's fine, but remember that if you're linking to the assignment through Blackboard students won't see that opening page. They'll be taken directly to the assignment.
Second, it pops up in a window when they open the assignment:
Notice that the top is what I wrote. The bottom part, about the number of comments, was added by Perusall because I unchecked this box in the course scoring advanced settings:
So, if you uncheck this box, there is no need to separately type the number of comments required in the "instructions for students" box.