Apt-get :: Apt-get update

i am linux beginer,
1: I instaled DSL on HD
2: Bash sudo su
3: I have downloaded the compressed dpkg file ,and moved it to '/var/lib/', then uncompresset it:
tar zxvf dpkg.tar.gz

After 'apt-get update' comes command not found.
What i make wrong?

I usually just use the menu apps->tools->enable apt or apps->tools->synaptic (for graphical front end). These are the easiest ways I believe. After doing this edit sources.list to get the "Testing" sources, do this in your terminal:

cd /etc/apt/
vi sources.list
remove the # on the testing line
and make a # on the stable

then
apt-get update
apt-get install "name of the program"

Hope this helps.

Thak you for answering,
I have done this like you said, but i have still problems.
This baton ( Apps>Tools>Enable Apt) i have use, after typing "Apt-Get Update" come Command nod found.
Then I tried (Apps>Tools>Synaptic) then appears a window with: (Calling the dpkg restore script... Downgrading apt back to version 0.5.4... wget: ftp.debian.org: Hostname lookup failure An error occured while tryung to get apt downgrade press return to continue....:)

This dont exist:
(cd /etc/apt/
vi sources.list
remove the # on the testing line
and make a # on the stable)

is it necessary to have an Internet connection to fix it?
I use DSL with old Laptop und it have non possibility to connect wit Inet.
Please Help.

mine gets an error right off the bat when i try a install update

original here.