Assuming you have access to the (legally, of course), here is your 8-week study plan.
Every few chapters, you encounter review sections formatted exactly like the actual JLPT N4 grammar and reading sections. nihongo challenge n4 grammar pdf
The practice exercises at the end of each chapter perfectly mimic the actual question formats found in the JLPT exam. Assuming you have access to the (legally, of
: Every few units, there are review sections modeled after the actual JLPT exam format. 📖 Structure of the Book nihongo challenge n4 grammar pdf
The Nihongo Challenge grammar PDF is excellent for recognition (seeing a grammar point and knowing what it means). However, it is weak on production (writing your own sentences).