If you have successfully completed Minna no Nihongo 1 (Lessons 1-25), congratulations—you have crossed the beginner threshold. Now, you are ready for the intermediate level. The second book, Minna no Nihongo 2, covers lessons 26 to 50 and introduces essential grammar for daily conversations, keigo (honorific language), conditional forms, and complex sentence structures.
While I can't provide specific details on lessons 26 to 50 without access to the textbook, "Minna no Nihongo 2" generally continues to build on the foundational grammar rules introduced in the first volume. This typically includes: minna no nihongo 2 lesson 26 to 50 pdf grammar link
Many language schools in Japan (e.g., Sendagaya, ISI) provide free grammar summaries for students. Search for: Master Intermediate Japanese: The Ultimate Guide to Minna
Lessons 46-50:
Mastering Japanese N4: Minna no Nihongo II (Lessons 26–50) Lesson 26: Potential Form (Can do) 2
The series concludes with Keigo, the formal language essential for working in Japan: