Keywords work like the index at the back of a book. For a book on Metadata Central, you would go to the back, then to the A's perhaps, find "Admin", and then see "Security" under that. Instead of referring you to a page in a book, Help Meister lets you click on the keyword "Security" and go right to the page about it.
This is also how most desktop software help works. For MS Windows programs, for example, you click on "Help" and then "Contents" to see the keyword index.
In the picture below, the user has clicked on the "Keywords" command button to get an alphabetized list of keywords. Then he clicked the plus icon to expand "Admin" to reveal "Security" listed hierarchically below it.
When he clicked on the keyword "Security", Help Meister showed all the help records that were entered with the keyword "Security". The fifth one down is "Security Level". Clicking that would show the help record of the previous slide.
The same help record may be listed under more than one keyword, much like a page in a book may be listed in the book's index under more than one keyword. If it took you a while to find the help record you sought, suggest your Admin person to add a keyword that would have helped you, and to list the help you needed under that keyword.
To the right of the "Keywords" command button is the "Search" button. Click on Search, the next slide along the top, to see how this provides another way to find the help you need.