In order to trace the patterns, I use compostable parchment paper or tissue paper as I usually have some on hand. Don't forget to check if seam allowances are included on the pattern sheets or not (often they are not with these patterns, because smaller pieces fit better on the sheets).
I've written about Japanese sewing pattern books a few times before. This is maybe the most comprehensive past post. They are one of my most favorite sources for little girl's clothing patterns in particular.
Since I don't have everyday access to brick + mortar shop where I can browse through these books, my library is the most accessible place to look. Our library system has a small selection, but both of these were requested through interlibrary loan.
Amazon can be a good source of both the books + peeks inside the books. Another good source is Etsy. This shop + this one in particular offer a lot of books + peeks...but there are others as well. Search "Japanese pattern book".
These two books have been translated into English, while some of the others are in Japanese. All of the diagrams + numbers are simple enough to follow in either language (in my opinion).