Hello Gabriela,
To add a connector that you'll use later on, select the Connector Tool on
the Standard toolbar (a line with a small white square at either end), hover
the mouse over the centre of the shape until you see a red square
encompassing the whole shape, then left click and drag down to your end
point.
To draw a line you can use the Line Tool on the Drawing toolbar
(View/Toolbars/Drawing if it's not visible).
Best regards
John
John Goldsmith
www.visualSignals.co.uk