。
Yumi will use this camera tomorrow afternoon.
Literal
Yumi [topic-は] tomorrow-of afternoon this camera [object-を] use-[conjectural-でしょう].
Despite being paired with a future time expression, Japanese uses the non-past form 使う. The でしょう adds a slight predictive nuance — not quite 'definitely' but 'probably/expected.' Very textbook-flavored; the kind of sentence used to drill time expressions and でしょう.