Most documents consist almost entirely of running text—words formed into sentences, which are in turn formed into paragraphs—and the example file is no exception. Describing running text poses no problems, you just type it in naturally. In the output that it produces, LATEX will fill lines and adjust the spacing between words to give tidy left and right margins. The spacing and distribution of the words in your input file will have no effect at all on the eventual output. Any number of spaces in your input file are treated as a single space by LATEX, it also regards the end of each line as a space between words (see lines 15–17). A new paragraph is indicated by a blank line in your input file, so don't leave any blank lines unless you really wish to start a paragraph.
LATEX reserves a number of the less common keyboard characters for its own use. The ten characters
# $ % & ~ _ ^ \ { }should not appear as part of your text, because if they do LATEX will get confused.