I think any English grammar book should explain verb phrases and prepositional phrases, but I am not sure about compound idioms. Prepositional phrases are used to give more details about where, when, and why. For example, "I like to eat eggs in the morning". The prepositional phrase "in the morning" is more detail about when I like to eat eggs. In English, prepositional phrases start with a preposition. Common prepositions are "in" "on" "after" "for". A "verb phrase" might be a few different things, depending on the book. There is also something callsed "verbal phrases". I have never heard of a compound idiom. Normal idioms are just phrases or expressions where the language doesn't quite make sense from a logical point of view. These are expressions that mean something that doesn't match the literal meaning. For example, the word "cool" is an idiom if you say "That dress is so cool!" because you probably mean it is a fashionable dress and not a dress that keeps you from getting too hot. Maybe a compound idiom is an idiom made up of more than one word or expression.