> I am on linux mint and do not have root.
> I am new to terminal ...
So what do you know, what experience do you have, and what are you trying to achieve?How much of this are you familiar with?
http://en.wikibooks.org/wiki/Linux_For_Newbies/Command_Line
Without knowing the package you're trying to install, and then going away to install it myself and noting all the steps in minute detail, any assistance will have to be generic, and will depend on how much you already know.
Why are you on Mint, and yet not have root access?
For reference, there's also this: