Reading the Wiley textbook is going to take time and depending on when your exam is you probably need to get out of the funk and start studying.
I switched to Wiley after failing audit multiple times and realizing I really didn't know anything. I read the Wiley textbook cover to cover. I read each chapter and took notes. When I had a hard time grasping the concept I looked it up on google or asked on the forum. As I was going through the textbook I did progress tests. The Ninja MCQs are structured different so the chapters are not going to always align. I would drill down and do a custom quiz and I would pick the chapters I wanted to get questions from. I did the questions in sets of 10. I got through at least 50 questions for each chapter my first go around. I just made sure I understood the material. After I was done reading the whole book, I focused on just questions. My attention span is terrible so I stuck with the 10 sets and worked as many as I could each night.
I was exhausted and finally after years of studying I truly understood what people meant when they said they were burned out from studying. I went from a score in the 40s to a score in the 70s. I keep getting awful FAR related sims which is part of the reason I didnt pass. However, for me working the Ninja MCQs till I was blue in the face is what really made the difference.