A method for assembling a single-detent binder includes assembling ring shaped components and first and second baseplates to a housing. The first and second baseplates are longitudinally adjacent and parallelly arranged and connected to each other. The first and second baseplates include adjacent longitudinal edges and non-adjacent longitudinal edges. The first and second baseplates are so assembled as to pivot around the adjacent longitudinal edges in order to open or close the ring shaped components. The ring shaped components each include two half ring shaped elements. The half ring shaped elements each are fixed on the first and second baseplates and pass through the housing. The half ring shaped elements occlude to form a closed ring, and the half ring shaped elements disjoin to form an opened ring. The method further includes assembling the control component to the housing, rotatively connecting at least one rotary locking piece to a pull rod, rotatively connecting the rotary locking piece to one of the first and second baseplates, and operatively connecting the pull rod to the control component. The control component includes a handle, which enables the control component to rotate relative to the housing. Assembling the ring shaped components and the first and second baseplates to the housing are performed simultaneously with rotatively connecting the rotary locking piece to the pull rod.