Complex sentence: Before Martín went to the meeting, he watched the news and saw that Salvador was Ángel, then he broke the artwork and saw the camera he knew he was found out, so he called his mother and told her that they had to leave the country.
Split into simpler sentences: Before Martín went to the meeting, he watched the news and saw that Salvador was Ángel, then he broke the artwork and saw the camera. He knew he was found out, so he called his mother and told her that they had to leave the country.