Locate your license file that was sent to you when you purchased the library. You will need both the license number as well as the registered license mail as stated in the license. Your license information should look similar to:

----------------------------------------------------------
: Your license key : JPGP-0920-1234657  
:  Name on license : A. JpGraph User 
:           E-mail : jpgraph-user@example.com
----------------------------------------------------------

Point the browser to http://jpgraph.net/pro/login.php and enter your licence email and key on the website.

Figure 3.1. Pro-login dialogue on JpGraph Website

Depending on your system you should now download either the 1.x or the (preferred) 3.x series. There is a choice to either download the library as a "*.zip" file or as a compressed "*.tar.gz" file (which is the preferred format in a Unix environment). Save the downloaded file to a temporary directory of your choice.

[Optional] Verify your downloaded file against the given MD5 sum on the website. On a Unix system this can be done by running the md5 program and give the downloaded library as the argument.

For example: $> md5 jprgaph-3.0.0p.tar.gz

Unpack the library to a suitable directory that is in your PHP include path as is described in Installing the library