Go to [https://lucid.app/](https://lucid.app/) and log in to your account.
Select the diagram you want to add a hyperlink to.
Click the "Shapes" button in the top left corner of the page.
Select the shape you want to add a hyperlink to.
Click the "Link" button in the top right corner of the page.
Enter the URL of the page you want to link to in the "Link" field.
Click the "Apply" button.