having trouble installing acrobat 8 to my macbook

Hi I just bought a macbook its 2nd hand off a company trying to recover money and they included programs like adobe acrobat, illustrator, in design etc

I apologise for the length and quantity of questions. I am very lost and arent finding answers anywhere online..

I have a small list of instructions they gave but im lost, i firstly burnt them to a dvd for backup reasons, the programs were in a folder on desktop,

first instruction was to drag the file to desktop and open dmg file-says from desktop it will install
but i dont think it has installed as hasnt asked me for the activation codes they provided me with..

In the help field i found the following;

'drag the adobe acrobat 8 professional folder to the applications folder at the root of your hard disk, open the folder and double click the adobe professional icon'

Q1-on desktop i have an icon called macintosh hd, does this mean hard drive or hard disk?
Q1a- are they the same thing?

Q2- what do i do to install? do I open the icon macintosh hd, then open applications and drag the acrobat.dmg there?

and hope you dont mind but for the other programs it says 'you can install from the external drive or dvd, find the prgram file then open 'setup'

Q1- what is the external drive?

thank you for your help and time it is muchly appreciated!

tazioak