If a step in a use case refers to another a separate use case (for example, a single step in a use case might be described in detail by a separate use case), you can insert a link to that separate use case. To create a use case link, right-mouse-click on the step you want the reference inserted and choose Insert Use Case Link (Shortcut: press Ctrl-L to add a link to the use case step where the editing caret is located).
You can edit the inserted text to make it grammatically correct. Navigate to the linked use case by clicking on the blue underlined identifier. Hover over the blue underlined identifier to show the use case description in a tool tip.