Complex sentence: Charlie Waller took over as head coach, but after finishing 5-6-3, he stepped down, and Sid Gillman returned to the job, but he quit halfway through the 1971 season, which ended with six wins and eight losses.
Split into simpler sentences: Charlie Waller took over as the head coach, but after finishing 5-6-3, he stepped down, and Gillman returned to the job. Gilman resigned midway through the1971 season, which ended with six wins and eight losses.