Complex sentence: Executive Order 12866 describes OIRA's role in the rulemaking process and directs agencies, to follow certain principles, such as consideration of alternatives and analysis of impacts, both benefits and costs.
Split into simpler sentences: Executive Order 12866 describes OIRA's role in the rulemaking process. In it, the President directs agencies, to follow certain principles in rulemaking, such as consideration of alternatives and analysis of impacts, both benefits and costs.