As I understand things apt uses dpkg are there any operations that you can do with dpkg that can't be done with apt? as a new User to Ubuntu server do I need to learn anything about dpkg?
In short, dpkg can do much more than apt-*.
Ubuntu and other Debian derivatives rely on the *.deb package infrastructure.
dpkg is the application that handles the packaging tasks of applications bundled in the *.deb files. You can do anything with it that apt can do, at a lower level. You can search, obtain information, view the files, extract, install, remove, configure, etc. with it.
dselect is a curses (terminal gui) frontend for dpkg.
Apt is the Advanced Packaging Tool. With it you can automate a number of steps you would need to do by hand to obtain the results with dpkg. Apt works with the *.deb packages found in repositories to the point that you may not even know the files are there.
aptitude is a curses (terminal gui) frontend for apt-*.
synaptic is a gtk+ (desktop gui) frontend apt-*.
Notable usage for dpkg:
Notable usage for apt-get:
Notable usage for apt-cache:
Otherwise, don’t worry about it. If you know your way around
In other words,