modifier are confusing

I see nothing wrong with that sentence.  

http://www.writingcentre.uottawa.ca/hypergrammar/modifier.html

A modifier can be an adjective, an adverb, or a phrase or clause acting as an adjective or adverb In every case, the basic principle is the same: the modifier adds information to another element in the sentence.

In this chapter, you will begin by working with single-word modifiers -- adjectives and adverbs -- but the information here will also apply to phrases and clauses which act as modifiers.

Before publication, the article is reviewed by a panel of experts to determine its credibility.

This is more clear.