To install or remove packages you need root user permissions, so your user needs to be in sudoers or you must be logged in as root.
APT keeps a list of software sources on your Pi in a file at /etc/apt/sources.list. Before installing software, you should update your package list with apt-get update
To install a package use sudo apt-get install packageName
Typing man packageName gives the manual of the package
Typing whereis packageName shows the location of the package
To uninstall a package use apt-get remove packageName and to completely remove apt-get purge packageName
To get update all the packages installed type apt-get update or apt update for a full try apt full-upgrade
To install the update type apt-get upgrade or apt update you can also use rpi-update to upgrade the firmware for your Raspberry Pi.
To update specific package type apt-get install packageName
To search archive of package type apt-cache search packageName
To resolve/fix a broken update use apt-get uopdate --fix-missing
To automatically removed the dependent module not required by the system use apt autoremove