Complex sentence: When the pair moved to Mexico and opened up a chain of Los Pollos Hermanos chicken restaurants together, Max is the chemist; he cooked the crystal meth, samples of which he and Gus started giving away.
Split into simpler sentences: When the pair moved to Mexico and opened a chain of Los Pollos Hermanos chicken restaurants together. In the drug business, Max is the chemist; he cooked the crystal meth, samples of which he and Gus started giving away.