You can do that, in most instances. First select the row below which you want the new rows, plus more rows above that, up to the number of rows you want to insert. That is, if you want to insert three rows, select the three rows immediately above the place where the new rows will go. Then move the mouse pointer into the left margin next to the lowest of the selected rows, and click the plus-in-circle icon.
As an example, I want to add three new rows between rows 5 and 6:
When I click there, I get this:
The case where this doesn't quite work is if there aren't enough rows above the insertion point. For that, just point to the plus-in-circle at the insertion point and click it multiple times.