Currently the only guide we have for installing squid on Ubuntu is written for an old version and would not likely work with more recent releases of Ubuntu. Since you have not shared what guide you attempted to follow, what issues you encountered or any errors that were displayed, assisting you in resolving this will be quite difficult. If you’re running Ubuntu 16.04 I would recommend starting with the official Ubutnu guide here which guides you through the basic steps to get squid up and running. If you encounter trouble while doing this, let us know which step you are stuck at and any relevant errors or messages that you are seeing and we’ll be happy to help you get them resolved and get squid up and running.