Hi,

If you downloaded a book in pdf form through online channels firstly you will get notification after successful downloading you can click on it to open it. in second way open your chrome app as you can see three dot icon on your top right side click on it there you can see downloads option there you can see the list of downloaded files another way is open file explorer in your device there you can see different files here you can search the book file with name of file or you can just scroll through it to find it.