How to clone a modem and download certificate from an online modem?

Hi,

I have spectrum internet. I use arris sb6141 modem. I want to clone another modem. How to clone it? My modem is online. How to download the certificate from the online modem? How to upload the certificate to my 2nd modem? How to upload config file to my modem? How to uncap my modem speed?

Thanks,