I feel a bit ambivalent about sharing this up front, since part of the experience of reading Faulkner for the first time is experiencing the build-in frustrations and disorientations (what Philip Weinstein calls the process of “unknowing” in modernist work), but to help your sense of “when” you are in the first two sections especially, here’s a chronology derived from the novel:

CHRONOLOGY: The Sound and the Fury

1890 Quentin born.
1892 Caddy born
1894 Jason born
1895 April 7, Benjy born.
1898 Damuddy’s funeral. Caddy in the pear tree with her muddy drawers.
1900 Benjy’s name is changed.
1900-01 Natalie episode.
1906 Caddy in swing with Charlie. Episode with Benjy and Caddy and the use of perfume.
1908 Benjy, now 13, must sleep alone. “You too big to sleep with folks.”
December 23: Uncle Maury – Mrs. Patterson affair. Benjy and Caddy deliver a message to Mrs. Patterson which is intercepted by Mr. Patterson. Uncle Maury appears with a black eye and a bloody mouth.

1909 Caddy loses virginity. Benjy’s knowing.
Fall: Quentin enters Harvard.
1910 April 25: Caddy’s wedding. Benjy and T.P. drunk.
April- May: Benjy at the gate. He attacks the Burgess girl and is castrated.
June 2 : Quentin’s suicide.
1911 Quentin’s birth ( Caddy’s daughter)
1912 Death of Mr. Compson. Dan howling.
1912-1914 Trips to cemetery begin. T.P. driving carriage with Mrs. Compson, Benjy.
1915: Roskus dies. Luster sees his ghost.
1928: April 6-8: Time present. Golfers, the lost quarter, Benjy’s birthday.
April 6: “Jason’s section”, April 8: “Dilsey’s section”.