The first time you open a new app is the only time you get to make that impression, and most people spend it poking at settings with nothing loaded. FoxLeaf is not available yet, so this is a chance to think about the first listen before you are in it. None of this is required. It just makes the first fifteen minutes better, and the first fifteen minutes decide whether people keep going.
Pick a book with rooms in it. The single biggest factor in how good an illustrated audiobook looks is how much the prose describes. A story that moves between physical places, with weather, buildings, and people in them, gives the engine something to render. A dense philosophical essay does not, and that is not a failure of the app so much as a mismatch. Classic fiction is unusually strong here, because writers of that era described everything: their readers had never seen a photograph of the place. Adventure, gothic, mystery, and travel writing are the safest first picks.
Start in Foxy's Library rather than your own files. The library is built into the app and opens onto the public domain catalogs from the Internet Archive and LibriVox, so you can be listening within a minute of installing without buying or transferring anything. Use it to find out whether the whole idea works for you. Bringing in your own audio files is worth doing once you know, not before.
Give the art style thirty seconds of thought. There are twelve, and the difference between the right one and a random one is larger than it sounds. Match the register of the book: something soft for a gentle story, something heavier for a mystery. You can change it mid-listen without restarting or losing your place, so this is a low-stakes decision, but starting with a style that fits sets the tone for everything after.
Decide where you are going to listen. This is the question most people have not considered, because with pure audio it does not matter. It matters here. Phone in hand is the default. Phone propped up while you do something with your hands is the mode a lot of people settle into. Mirrored to the television is the one that surprises people, especially with someone else in the room. Try at least two, because the right answer is personal and rarely the one you assumed.
Plan for a real session, not a two-minute look. The things FoxLeaf is built to do only become visible with time: characters holding their appearance across chapters, scenes changing when the story turns, coming back after a break and recognizing where you are. A two-minute sample shows you a picture. Half an hour shows you the product. If you can, give the first attempt an actual sitting rather than a hallway test between other things.
FoxLeaf is coming soon to iOS and Android, and this will be waiting for anyone who wants to walk in prepared.