、。
Inside the church, she sat down beside me.
Literal
Church [genitive-の] inside [at-で], she [topic-は] my [side-そば] [at-に] sat.
An unusual sentence-front placement of the locative phrase 教会の中で ('inside the church') — Japanese allows scenic openers like this, similar to English fronting 'In the church, she...'. Two locative-particle distinctions are at play: で marks the broad setting (the church, where the sitting happens), while に marks the narrow position (her destination — beside me). 私のそば ('beside me') uses そば ('side, vicinity') as a relative-position noun with the genitive の.