For students, the books that appear when selecting a category and subcategory in Browse will appear in order of most relevant to least relevant in regards to year level and the student's Star Reading or Star Early Literacy Zone of Proximal Development (ZPD) (if you have linked the Star score). That means the closer to the top of the page, the more relevant the book is to your year and ZPD. As you scroll down, the book levels will become less relevant and will fall out of your year level and ZPD.
Teachers using the Browse tab can select a year/reading level at the top of the page to get the experience that students at that level would get.