جَاءَنِي الرَّجُلَانِ كِلَاهُمَا وَاثْنَانِ.
Translation: The two men themselves came to me, and two others also came.
الرَّجُلَانِ: subject (fāʿil), nominative, marked by alif.
كِلَاهُمَا: an emphatic expression referring to both men; nominative with alif.
اثْنَانِ: coordinated with wāw; nominative with alif.
Observation: The book combines several nominative examples into one demonstration sentence; simpler everyday sentences will follow.