Complex sentence: The second diploma, the BEP, requires 3 years of study after the "collège" and leads to a professional qualification in a specific field, such as the restaurant industry, metallurgy, et cetera.
Split into simpler sentences: The second diploma, the BEP, is prepared for during 3 years, after the "collège". It leads to a professional qualification in a specific field, such as restaurant industry, metallurgy, et cetera.