I think when you first learn about this job, you knew nothing.
Yes and no.
Fairly quickly after I joined this forum I became part of the management of the crypto-games.net signature campaign.
I had the chance to be involved in managing one without being the actual guy in charge, which allowed me to pick up on most things I needed to know.
I wouldn't have taken on a signature campaign on my own back then, so if it wasn't for that, I might not be a manager today.
Little time later, I was co-managing my second campaign, aka supporting mexxer in the ones he managed.
By the time I took over the cg campaign completely, I've already had quite some experience, which paid off, more offers began to fly in.
Which leads us to the important point:
you don't get to choose if people want you be a campaign manager, it just happens
Exactly this.