We would like to examine the documentation of the geometry package. At first, we shall look for it locally on our computer. Afterwards, we will see how to find the documentation online:
Click the Start button and choose All Programs | Accessories | Command prompt
Type the following:
A PDF viewer should start and show the package manual. The same command works at the command prompt on Linux/Unix computers.
Hit the Start button again; this time, choose All Programs | TeX Live 2010 | TeXdoc GUI. Click on Search texdoctk's database, enter the keyword geometry, and press Enter:
Have a look at the search result. Open it by double-clicking or hit the View button. A viewer should open the documentation.
Open an Internet browser and visit the site http://ctan.org/pkg/geometry. Scroll down to Documentation on CTAN and hit the link User's manual. Again, your PDF viewer or a browser plug-in will show the documentation.