When training your character your Experience points determines various statistics about your hero.
The base statistics of your character is the combination of your race and your class. However, the starting statistics of your and is capped at 5. So if your race provides 4 points in and your class provides 3 points, then your attack stats will be 5, not 7. The same cap does not apply to Health and Stamina.
When training, you use the level table to see what stats each amount of Experience points amounts to, many levels are the same and progression may seem slow. There are items in the game that temporarily or permanently alters your statistics as well, which needs to be taken into account to when training.
For each level in the table, you unlock new abilities as well, in the form of a new card for your race and a new card for your class. These cards can not be added to your hand, but they are available to you. The amount of cards on your hand is determined by the number of Level 1 cards available from both your race and your class. If you obtained 5 level 1 cards from your race and 4 level 1 cards from your class, then your hand is capped at 9 cards, and new cards unlocked may replace any on your hand.
There are also item cards available to certain character levels, and only unlocks when you have reached that particular level, at which point they become available to purchase by any member of your group. These cards may contain abilities, augmentations or other effect, but never actions and thus does not go on your hand.