I am new to Linux and become a recent user of Ubuntu 18.04.4 LTS, Gnome 3.28.2 Ver. with VTE Ver. 0.52.2 + GNUTLS-PCRE2 and need advice

I am confronted with my 1st ERROR as detailed below and need support in troubleshooting the issue:

"Error: Opening the cache (E:Couldn't create temporary file to work with /var/lib/apt/lists/in.archive.ubuntu.com_ubuntu_dists_bionic_InRelease - mkstemp (30:Read-only file system),E:The package lists or status file could not be parsed or opened.)"
This usually means that your installed packages have unmet dependencies.