If you've claimed them in the LoN game, you can look at your Claim Rewards in the EQ button. Select the item you want and hit claim. The character you claim it for should then receive it. You need an open inventory spot to get it.
If you want to get into the game itself, once you start it up, you can click on the tutorial to learn how to play the game. If you have any cards that you have claimed in the game, you can go into the card manager and it'll list all the cards you have. If any of these are in-game loot cards, they'll be listed as well. If you want them available in-game, you just right click and claim. Follow the steps and then you can continue as above and receive them.
If you don't have any in-game loot cards, you can try to get them by purchasing boosters from the LoN website
http://legendsofnorrath.station.sony.com/ However, in-game loot cards are extremely rare. If you have the plat, you can try to purchase them from other players, but sometimes they ask for way too much for their value.
Hope this helps. Good luck
Edited, Jan 12th 2009 2:46pm by Ipthar