Crew battles work like this:
Each people assemble a team of X amount of people. Each person gets whatever stock they agree to have matches on (in the case of Melee, 4 Stock matches, so 4 for each person, and you can add it up also for the crew/team's total stock.)
So, one person plays another person, and whoever wins continues to play the next person from the other crew. But they have to suicide to how many ever lives they had remaining in the last battle (the % doesn't matter.) And then it keeps going from there until one team is all out of people/stock
Hope that made sense and cleared any confusion.