STL County Fire Academy Confusion?

What does "new hires from St. Louis County Fire agencies" mean?

It says elsewhere, “The first is to be hired as a full-time, paid firefighter by a fire service district in St. Louis County.“

So can you just work at a firehouse in any capacity? Really - Is there any way to go through the academy while being paid and/or without having to pay?

ISO answer for fiancé. He is waiting on STL City but exploring other options.