To activate a hyperlink using the keyboard:
(1) First click inside the link with your left mouse button,
or move the text cursor inside the link using your keyboard,
or select/highlight the entire link-text with your mouse,
(2) then press "Ctrl H" on your keyboard
Here is an example hyperlink to the TreePad.com home page:
First select this link using any of the three methods described in point (1) above, then press "Ctrl H" on your keyboard.