digi tacho

can any one give me an idiots guide to using a digital tachograph . ive just had my digi card, but havent got a clue how to use a digital tachograph. is there a web site on how to use one ? or can some one give me the basic details of how to use one please. cheers kev.

look here trucknetuk.com/phpBB2/viewtopic.php?t=20451
it was covered on here a while back