Usually, in a conclusion, you wrap up what you have been writing about the whole time. So, a conclusion is basically a summary of the whole text. You can introduce new ideas for the reader, but it is usually inadvisable. In a couple of sentences, you should finish your text, referring to the previous paragraphs and just wrap it all up nicely.
You can use breaks in Microsoft Word, e.g, and also you can use blank when you want to start a new paragraph. But between two words, you can use only one blank.
