If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.
If a creature you control would enter the battlefield with a number of +1/+1 counters on it, it enters with twice that many instead.
If two or more effects attempt to modify how many counters would be put onto a creature you control, you choose the order to apply those effects, no matter who controls the sources of those effects.
If you control two Branching Evolutions, the number of +1/+1 counters put on a creature is four times the original number. Three Branching Evolutions multiplies the original number by eight, and so on.