Complex sentence: Before then, every year in September, a large number of new university freshmen acquired access to Usenet for the first time, and took some time to become accustomed to Usenet's standards of conduct and "netiquette".
Split into simpler sentences: Before then, every year in September, a large number of new university freshmen acquired access to Usenet for the first time. These took some time to become accustomed to Usenet's standards of conduct and "netiquette".