Link to note
To create a link to a note, you have two options:
Create a Markdown link
Simply create the link in Markdown, as described in the Markdown guide.
Use the "Link to note" dialog
An easier way is to use the "Link to note" dialog - to do so open the dialog from Tools => Link to note.... Then type the note you would like to link to and press Enter when done.
This will create a new link and insert it into your current note.