。
The room must be kept tidy.
Literal
Room [object-を] properly do [in advance-ておか] must.
Uses ~なくてはならない, a variant of ~なければならない with identical meaning. きちんとする means 'to be proper/tidy' — きちんと is an adverb meaning 'properly, neatly.'
。
The room must be kept tidy.