Complex sentence: At that point the river enters Bangladesh through the Lalmonirhat District and then joins with the Dharla River and flows as the Dharla River before it debouches into the Brahmaputra River near the Kurigram District.
Split into simpler sentences: At that point the river enters Bangladesh through the Lalmonirhat District. After entering Bangladesh, the river joins with the Dharla and flows as Dharla before it debouches into the Brahmaputra River near Kurigram District.