Well, you can show up with zero knowledge of ballooning, and the pilot will be grateful for your help. Ballooning is hands-on, blue-collar flying; there is a fair bit of manual labor involved.

At the other end of the spectrum, experienced crew might be charged with pretty much the entire operation of the balloon until it leaves the ground, and as soon as it touches down again, as well as driving/navigating the chase vehicle, landowner relations, weather observation. They can also participate (under pilot or repairman supervision) in inspections, maintenance, minor and major repairs, and all sorts of other ancillary tasks.

As for the pilot, there are all sorts of considerations. For example, the wider the difference between ambient temperature and envelope temperature, the more lift we can produce. But, we have a maximum allowable envelope temperature, so if it hot out, we can't get as wide of a temperature delta, and can't reach as high of an altitude. We can't steer except by changing altitude. Do we have enough lift to reach the altitude layer with favorable winds?

On the flip side, the surface winds often differ significantly from the winds aloft, but if we are within 2000 feet of an obstruction, we have to maintain 500 feet above it. We've got a good direction toward a favorable landing zone right now, at treetop level but there is a 1000' tall antenna tower in front of us. When we climb, where are the winds going to take us?

I expected winds from 270, but the actual winds are from 315, taking me much further right than I had originally planned. Can I continue this flight? Do I need to descend below the floor of the outer ring, or can I stay up high? Do I need to land as soon as practical?

There is a beautiful field in front of us, but a quarter mile ahead, there are high tension wires. If I abort a landing into this field, do I have the climb performance to clear those wires?

I want to get low over the lake and trees for some good pictures, but the nearest landing site past the lake is 6 miles, and sunset is in 90 minutes. Do I have the time and fuel to descend and play, or do I have to stay high and fly on?

It gets more interesting when we introduce competition flying, where you're trying to reach specific points at specific times, or make the sharpest turn the winds will allow, or grab prize money from the top of a pole, or chase a leader with a head start.