@Thofte, I passed N5 last year. My resources were either practice questions, mock papers or a bit of both. There was a CD included for the listening test. I do not know how good the book you’ve chosen will be. The books I chose worked for me and I listed them in this post.
If you’ve already completed Genki II and you are at level 22 in WaniKani, you could be a candidate for N4. N4 speaking speed is a little faster than N5. If you just want to play it safe and do N5, here are some tips for listening from my N5 experience:
Use your Genki CD dialogues for listening practice. Use the shadowing exercises to recite aloud what they’re saying. It’s OK to read the text whilst you’re still learning to listen. Even though it is not a speaking test, reading aloud will help your listening.
N5 listening comprehension questions are two people having a conversation. A man and a woman. It could be a student and teacher, two students, two friends etc. The introductory part of every questions is the same.
They are usually deciding what to do from a number of options. e.g. what to buy as a gift, where and when to meet, what to bring or not bring, what to do next, what colour / size object, how many of which pill to take. The multiple choice questions will list the options.
The tricky thing is that the male speaker might say, “I like the red bag” and then the female speaker says “the blue one is better” and the male speaker finally agrees without explicitly saying “I choose blue”. Then the question will ask you what did the male speaker choose. You have to listen carefully. Just because you heard the colour red mentioned in the dialogue and you see it listed in the multiple choice answers, does not mean it is the correct answer.
You only get to hear every passage once. When you practice at home, you can make it easier for yourself by reading the script for the dialogue and playing the dialogue as many times as you need. I suggest doing that with your Genki CD and saving the N5 specific CD for practising under exam conditions.
The real test felt harder than my practice ones because I was anxious. So relax and do as much practice at home as you can.