Examples are 河 hé "river", 湖 hú "lake", 流 liú "stream", 沖 chōng "riptide" (or "flush"), 滑 huá "slippery". All these characters have on the left a radical of three short strokes (氵), which is a reduced form of the character 水 shuǐ meaning "water", indicating that the character has a semantic connection with water. The right-hand side in each case is a phonetic indicator. For example, in the case of 沖 chōng (Old Chinese *ɡ-ljuŋ), the phonetic indicator is 中 zhōng (Old Chinese *k-ljuŋ), which by itself means "middle". In this case it can be seen that the pronunciation of the character is slightly different from that of its phonetic indicator; the process of historical phonetic change means that the composition of such characters can sometimes seem arbitrary today.
Where can you find info on pronunciation in the example characters?
The right-hand side