PVE Combat (AKA Ratting) means killing NPC's or Non Playable Characters. It is easily done by doing agent missions such as Intelligence or Security. Usually you start with level 1 missions and work your way up. They are really easy and will earn you some good starter ISK. If you finish the tutorial, the Cormorant will do nicely for these missions. For bonus ISK salvage all of the enemy wreckage and take their cargo. This will increase your ISK count substantially.