Generate an image
Tap the + in the middle of the bottom bar and choose Generate.
Describe what you want to see. Be specific about the subject, the setting and the mood — "a red fox asleep on a mossy log, morning fog, soft light" gives a far better result than "a fox".
Pick a model and a size, then tap Generate. Each generation costs credits, and the cost is shown before you commit. Your results are private until you choose to share them: they collect in your Library, under Generated.