At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher,  you are able to cast an additional bolt for each slot above 1st (also giving u the ability to hit multiple targets. you have to roll: amount of bolts devide by 2(round up), times to see how many bolts hit( 2bolts, 1 roll. 6 bolts, 3 rolls) hitting a/multiple target(s) goes per 2 bolts. When you cast this spell using a spell slot of 5th level or higher, the damage increases to a 2d8 +1. When you cast this spell with a spell slot of 7th or higher, the damage increases to a d12+2d6+1. When you cast this spell using a spell slot of 8th level or higher, your amount bolts halves(round down) but your damage increases to d12+2d8+ 4