Complex sentence: Advanced EMTs must be certified as EMTs prior to seeking certification as an AEMT in most states, which involves a class lasting from three to six months, the curriculum for which is largely outlined by the NAEMT but can vary slightly from state to state.
Split into simpler sentences: Advanced EMTs must be certified as EMTs prior to seeking certification as an AEMT in most states. Certifying as an AEMT involves a class lasting from three to six months, the curriculum for which is largely outlined by the NAEMT but can vary slightly from state to state.