you were reading from the "talk" page, not from the instructions. If you look at the tabs there you will see the tab for the actual article, and the tab you were on makes some mention that what you were reading is obsolete but kept there for reference purposes.
Go bak to the actual doc and you will see very simple instructions. All you need to do per the instructions is to put the zip file on your moodle root and unzip-then you can fiddle adminlib.php if you like.
How did you end up on the talk page in the first place?