where do I go on this site to see if a book is available and from what branch

You can use the search box with "Catalog" selected, or Browse > Catalog in the menu

The catalog. There is a search bar at the top of the akronlibrary.org. Type what you're searching for in that search bar and items will come up. You can limit your search to certain branches. But to see what books are at what branches, you will have to click on the book you're searching for and the branches that have the book will be listed, along with their status (check shelf, due back date, transit, etc). Also, the library can have books shipped from one branch another. Some times it's easiest to call and ask your library if they have an item available