I just discovered the Libby app, I love listening to audiobooks on my walks. But am I going through a learning curve. First I had a hard time finding an available book, till I figured out I could filter available books only. Although disappointed the ones I want to read are not available for weeks. Then I borrowed one that I didn't finish in time and now I want to borrow again and it's not available, I had like 4 hours left. I feel like I could benefit from some tips. Help!