。
She shouted at the children to be quiet.
Literal
She [topic-は] children [target-に] quietly [quotative-と] shouted.
The quotative と attaches to the content of the shout, here 静かに ('quietly'). 叫ぶ ('shout, cry out') is one of the verbs of speech that pair with と to mark what was shouted. Note the elliptical content: 静かに alone is a fragmented quote — a shorthand for 静かにして ('be quiet') or 静かに(しなさい) ('quiet down!'). In writing, especially fictional dialogue, only the most charged word of the shout is usually preserved with と.