Adding ties and slurs (liga)

Activate the  tools panel (using the mouse or the Alt+N hot keys).
First select one of the «Slur»(«Liga»),  buttons so that your cursor is ready to tie the notes together.
Move the cursor over the first note to tie and press the left mouse button. Then either.

• release the mouse button and click the second note to tie, or

• do not release the button, move the cursor to second note to tie, and release it