Hey DKwan,
first of all, thank you for the purchase, and my apologies for a slow reply here!
regarding your question – initially, Kanso was not meant to have menu items that lead outside of the one-page layout, while the one-page mode is activated, in order not to confuse the users; however, following buyer requests I did develop an upgrade that would allow adding links to outside pages into the one-page menu – please refer to this forum post for details on how to install it. I will also include that feature into the upcoming 1.5 version update for Kanso.
Sincerely,
Andrii / Satori Studio