leverage broswer cashe

Can someone tell me how to set this date on these suggestions..........................see attached

<IfModule mod_expires.c>
    # enable expirations
    ExpiresActive On
    # expire images/css/js/swf files after a month in the client's cache
    ExpiresByType application/x-shockwave-flash "access plus 30 days"
    ExpiresByType text/css "access plus 30 days"               
    ExpiresByType text/javascript "access plus 30 days"        
    ExpiresByType application/javascript "access plus 30 days" 
    ExpiresByType application/x-javascript "access plus 30 days"
    ExpiresByType application/x-gzip "access plus 30 days"                                      
    ExpiresByType image/gif "access plus 30 days"
    ExpiresByType image/jpeg "access plus 30 days"
    ExpiresByType image/png "access plus 30 days"
    ExpiresByType image/x-icon "access plus 30 days"
    ExpiresByType image/vnd.microsoft.icon "access plus 30 days"
</IfModule>

Taken (and you can read more) from here: http://www.boonex.com/trac/dolphin/wiki/HostingServerSetupRecommendations

I recommend you give it a read.