napalkkoch on "[Plugin: WordPress SEO by Yoast] The keyword doesn't appear in the first paragraph of the copy."

First start by switching from Visual Editor to Text Editor.
If for instance you start your page/post with an Heading2, you need to correct the coding in the text editor, because you will probably have this: <h2>text+keyword</h2>

when you should have this:
<h2><p>text+keyword</p></h2>

That should solve your problem.