Mainly used on your first turn to summon Sunrise or DPE, or to summon Trinity on your second turn if you are pushing for lethal
Otherwise, I don't have much else to say
Buy Cards at the Shop Spend Gems at the Shop to purchase card packs
With the extra space it allows you to just bring them all and make the decision later
KEEP IN MIND this locks you into dark heroes for the rest of the turn, so make sure you already have all the non-dark monsters on the field you want first (Wonder Driver, Absolute Zero, Sunrise, etc.)
DBGC-JP033 Ankoku Shinden Zararham / Zararham the Dark Temple Field Spell (1) While you control a monster equipped with Noble Arms of Light Dannel, your opponent cannot activate cards or effects during the Battle Phase