# If brothers live together

"If brothers live on the same property" or "If brothers live near each other."

# then the wife of the dead man must not be married off to someone

"then the family of the dead man must not let the widow marry someone" 

# must go to her

"shall have sexual relations with her" or "shall lie with her" 

# do the duty of a husband's brother to her

"do what the brother of a dead husband is supposed to do"