showmewatididwrong

Hi I just got my action replay dsi yesterday and I downloaded it successfully on my pc and i already had codes for it and they are already on my action replay but what does it mean to put a combination? Ex.(L+R)? Do i activate them on the home screen of da action replay or do i do it in-game? Because i clicked on the box where it says to activate codes and i did put " boot game with codes" but nothing happened I used the "complete pokedex" code but my pokedex didnt get complete