Ehrenreich doesn't intend to be a waitress at all when she starts looking for her first minimum wage situation because she remembers how physically demanding that work was when she worked as a waitress many years previously. After searching unsuccessfully for a position based on want ads that listed jobs that appeared as if they would be preferable, she realizes that most of those want ad positions
are not a reliable measure of the actual jobs available at any particular time...finding a job is just a matter of being in the right place at the right time and flexible enough to take whatever is being offered that day.
For Ehrenreich, the job that was offered was a position as waitress at the "Hearthside." The immediate need to start earning income of any amount forces the transition from highly educated, upper middle class observer to low wage server. Her on-the-job training consists of trailing one of the other waitresses, separating instructions regarding procedures to be followed from the personal dramas of the employees and customers she encounters.