Another question, I logged into my root directory and i typed apt-get update, after the update process, i guess the system just downloads and unpacks the files. Now my question is, i came across a forum that discussed a command called "apt-get upgrade" , what does this command do and is it similar to apt-update.
"apt-get update" updates apt-get's database, so that it knows what new packages have been released out there and where to get them from.
"apt-get upgrade" procedes to upgrading all your installed packages to the latest available versions (the information about which are drawn from the database built with apt-get update). Of course you can define only a specific package to upgrade instead of upgrading everything.
PS. Don't forget "man", you are not going far without it