Add random button (Squarespace)

My squarespace site requires at least a random button on a journal entry. I would prefer a proper navigation if possible. I'm looking for the work to be completed quickly with an immediate start and time estimate. Here's my comic page: [login to view URL] Please make yourself familiar with squarespace before you bid. I can give further details later. I want this work completed very soon, so please consider this. Thank you