From David Dorsey’s book. Students of S of S may want to give other designations to the sections.
A. Opening words of mutual love and desire 1:2-2:7
B. young man’s invitation to young woman to join him in the countryside 2:8-17
C. young woman’s night time search for young man 3:1-5
D. wedding day 3:6-5:1
C’. young woman’s night time search for young man, and their speeches of admiration and longing 5:2-7:11
B’. young woman’s invitation to the young man to join her in the countryside 7:12-8:4
A’. Closing words of mutual love and desire 8:5-14
There are other proposals such as this from Davidson http://digitalcommons.andrews.edu/cgi/viewcontent.cgi?article=1253&context=jats, which also contains a thorough review of literature.
A 1:2–2:7 Mutual Love
B 2:8–17 Coming and Going
C 3:1–5 Dream I: Lost and Found
D 3:6–11 Praise of Groom, I
E 4:1–7 Praise of Bride, I
F 4:8–15 Praise of Bride, II
G 4:16 Invitation by Bride
G ́ 5:1 Acceptance of Invitation by Groom and Divine
Approbation
C ́ 5:2–8 Dream II: Found and Lost
D ́ 5:9–6:3 Praise of Groom, II
E ́ 6:4–12 Praise of Bride, III
F ́ 7:1 [Eng. 6:13]–10 [Eng. 9] Praise of Bride, IV
B ́ 7:11 [Eng. 10]–8:2 Going and Coming
A ́ 8:3–14 Mutual Love