The United Auto Workers (UAW) is in the midst of a potentially-historic drive to organize in the Deep South’s auto plants.

But in a deeply conservative, right-to-work state, it might be tough to understand the process by which a workforce is represented by a union.

On Tuesday, the UAW announced that a majority of employees at Mercedes-Benz’s U.S. International (MBUSI) plant in Vance had signed union cards. That’s less than two months after the union began organizing at the plant.

About 6,000 people work at MBUSI, which was the first auto plant to locate in Alabama and Mercedes-Benz’s first in North America.

A few weeks ago, the union announced 30% percent of the employees at Hyundai’s Montgomery plant had also signed cards.

However, signing a union card does not mean someone had joined a union.

According to the National Labor Relations Board (NLRB), it is only the first step.

If at least 30% of workers sign cards or a petition saying they want a union, the NLRB will conduct an election. If a majority of those who vote choose the union, the NLRB will certify the union for collective bargaining.

This was the strategy chosen by the Retail, Wholesale & Department Store Union (RWDSU) when it sought to organize at Amazon’s Bessemer fulfillment center. Workers there have already voted in two union elections, both of which were contested.

A contest to be heard later this year could determine if a third union election is on the horizon.

The UAW’s strategy involves signing up 70% of workers at the plants.

“After 70% of our coworkers have signed cards and we have an organizing committee made up of workers from every shift, every job classification, and every group of workers in the plant, we demand that the company recognize our union,” a UAW flier states. “If they don’t, we file cards with the (National Labor Relations Board) and take it to a vote.”

According to the NLRB, an employer may voluntarily recognize a union based on evidence.

Once a union has been certified or recognized, the employer is required to bargain over terms and conditions of employment with union representatives.

Special rules apply in the construction industry.

As Bloomberg reports, Mercedes employees in Germany are covered by a union contract, have representatives on the company’s board, and elect members to a works council.