Download the installer from
http://www.mozilla.org/products/thunderbird/.
When the download is finished, double-click on the file to open.
If you have any programs running, close them as advised. Press next.
Read the agreement, and if you agree, check the box and press "Next".
Choose the "Standard" installation for default setup.
The installer will give some brief information before beginning installation.
Congratulations! Thunderbird is now installed on your computer. Press finish to start the software.
