There's many ways to develope clairaudience ability..
Close your eyes to minimize distractions, and focus your attention on the left and right sides of your head, just above your ears. Feel those areas "opening", like widening circles. Do you hear anything? You might not at first, it may take time and practice. What types of things will you hear, you ask? You might hear voices or muted conversation (often it's too faint to make out exactly what's being said), you might hear music (again, it might be faint), or a host of other sounds. Once you begin to develop this sense, don't be surprised if divine guidance comes in this way!