Complex sentence: A technical advisor is an individual who is expert in a particular field of, hired to provide information in that field to a movie or television director, to ensure that this area of knowledge is portrayed accurately in the production.
Split into simpler sentences: A technical advisor is an individual who is expert in a particular field of, hired to provide information in that field to a movie or television director. The technical advisor's task is to ensure that this area of knowledge is portrayed accurately in the production.