She makes it a habit to read the newspaper after breakfast.
Literal
She [topic-は] breakfast [possessive-の] after [in-に] newspaper [object-を] read [decided-ことにしている].
Another instance of ~ことにしている for a self-imposed daily routine. 朝食の後に ('after breakfast') sets the timing. 新聞を読む ('to read the newspaper') is a classic daily routine verb phrase. The pattern is very productive for describing any habitual practice.