The Atmel SAM4S16 instructions:

atmel.no/webdoc/sam4s16xplained/sam4s16xplained.html

On this page:

atmel.no/webdoc/sam4s16xplaine…n.section_cnm_vyg_xf.html

Say that the user should download CDC and Segger debugger drivers from this page:

segger.com/beta-software-version.html

I can download the CDC file but when I try to download the debugger driver stuff it asks for an 8-9 digit serial number.

Only thing is that the Atmel SAM4S16 Xplained does not come with any serial number. So how do I get the code I need to use this board?

WF1903

The picture you show would appear to be a different download page to the one I'm looking at (as advised by Atmel). They suggested:

segger.com/jlink-software-beta-version.html

(note the word "beta" appears in that - not sure why they suggested that but they did). That page does not have the text/links you show in your screenshot.

Dare I say it but this seems fairly typical of Atmel

BTW if I look at your main download page (the none "beta" one):

segger.com/jlink-software.html

I don't see that text/link there either. So where is the page shown in your picture?