Package Management – Install Offline Ubuntu 16.04 How to load apt-offline & install

I'm installing Ubuntu 16.04. I am looking for someone who knows that the offline installer and updates for system updates, mainly wireless drivers, are inherited since my wireless card is an ASUS PCE card. AC56.
When I'm offline to use the sudo apt-offline command, I get an "offline apt-offline" command. I have tried to install the package for apt-offline and the package is not found.
And finding that I need a generated Sig file, I can find the packages to download to update the system although the apt offline is not found during the installation. How to generate the offline file to create an update package to update an online system running Ubuntu. Thank you for working around welcome and the information on this are of great help.