Research any universities that offer curator's certificate programs. The curricula for each university will differ in terms of requirements, instructors, grading and time needed. Each university will allow you to request information about it's curator's certificate program online.
Attend the classes required for your curator's certificate. The program will generally include classes involving art appreciation, art history, business management and social/cultural contexts.
Complete your residency period. The residency period will allow you to work in an actual museum for a period of time and learn from real curators in the workplace. Residency periods will vary depending on the university you attend.
Complete the curator's certificate program in full to receive your curator's certificate. Generally, this will occur after you complete your residency, but you must consult your specific university program for more information.