the potions you win in your chests are used when you open packs and increase the chance of getting a gold foil card. I hate them but people say I'll be happy when chaos packs come out.
I pretty much do the quest and play my mana down to 75% each day. That is the capture rate when you hover over your dark energy crystals balance. It replenishes like voting power.
My advice, just play and get lucky and win your quests. Then look up tutorials about bronze level splinters. You can learn a little that way. At least I did.