1. It starts with the formation of a bargaining unit, a group represented by a Union for dealing with an employer.
2. It is legal for employers to try to persuade employees not to unionize. However, it is illegal for an employer to prevent employees from unionizing through threats, violence, and other coercive action.
3. An employer is required by law to bargain in good faith with a Union, although an employer is not required to agree to any particular terms. Once an agreement is reached through negotiations, a collective bargaining agreement (CBA) is signed.
4. After a CBA is signed, an employer can’t change details of the agreement without the Union representative’s approval. The CBA lasts for a set period of time with the Union monitoring to assure the employer abides by the contract. To learn more about collective bargaining and how Unions work, visithttps://www.justfacts.com/unions.asp.
5. As with many other organizations, Union costs are paid by member dues. How much those dues are is voted on by the members. On average they are about 2-3 hours of pay per month. Most Unions have paid staff to manage their operations. While some staff may be paid by Union dues, many members often volunteer for various positions within the organization.

An explanation of the certification process can be found on the NLRB website here.