Jobs and Experts

Trying out the Jobs and Experts plugin for a client and like what we see but have a few questions that I can't find answers for on any existing ticket. Our client has a jobs web site with quite a few options we are re-building.

1. I read that adding "Market Place" will enable the site to charge for listing ads. How as I can't see how its integrated.
I see this adds "Credit Plan" but how does this link to ads placed on site
2. How do you change the values of the period a job is open for?
3. You have categories but how can we add "types" as well. In effect another category

That's all for now, thanks