How does the EXP that I earn after I win a battle in Dragon Adventure or..

The EXP you gain is to level up items such as Health +1 and Blast 2+5. You need to equip these items to the characters involved in the battle. When you gain enough EXP, the items you're equipped with will level up. For example, your health +1 will become health +2 or +3, depending on how much EXP you gained. A good way to get a lot of EXP is to go on the Android Saga and do the scenario entitled "Cell Jrs. Attack" on game level three to gain the most EXP. It will be a "Free Battle" and you will need to select three characters from Goku, Vegeta, Trunks, Picollo and Krillin. Equip all of these characters except for goku with items you would like to level up. Equip goku with Equipment Slots +4 (or whatever's adequate), Halo and Master's Protection. You can either equip Goku with two "Blast 2 +10" to level them up or you could just equip him with "Blast 2 +19" and have an extra slot to equip another item but not level up as many items but make sure his Blast 2 is on 20. Equip him with other items at your discretion. To beat the five Cell Jrs. You just need to repeatedly use "Meteor Smash" with SS1 Goku. The reason you should be SS1 Goku and not SS2 Goku is because, with Halo, Meteor Smash consumes less Ki than in SS2 form and you need to consume as little Ki as possible to do as many Meteor Smash's as possible. When you win you will gain about 2000 EXP and that goes to every item every character is equipped with that was involved in the battle (Goku, Vegeta, Trunks, Picollo, Krillin), the EXP does not get divided between all of the items. Remember to set the game level on 3 otherwise you won't gain as much EXP.