Each of these cryptic clues has three parts:
1. A regular definition of the answer.
2. An indicator word (or phrase) that tells you this is a homophone (sound-alike) clue. This can be anything that hints at something being said, heard, loud, broadcast, and so on.
3. A string of two or more words (the fodder) that are either a homophone for the answer, or a synonym of a homophone for the answer.
For example, a clue for the word BARE might look like this:
Reveal noisy woodland creature (4)
1. "Reveal" is the regular definition.
2. "noisy" is the hidden-word indicator.
3. "woodland creature" is the fodder; a synonym of this is "bear," whose homophone is "BARE"
Note that the three parts of the clue can appear in almost any order, but the definition will always appear at the beginning or end of the clue (as with almost all kinds of cryptic clues).
In some homophone clues, the indicator will appear next to both the definition and the fodder (as in the above example); in those cases, you'll need to use other letters in the grid to figure out which homophone to use.