Step Two:

Choose a keyword

You'll want to add your own keywords not only to your title, but to your articles because most often the PLR articles you have received have not been written with any particular keyword or density in mind.
Keyword density refers to the number of times an identified keyword appears within a given piece of text relative to the entire length of that text. It is usually expressed as a percentage. Although there are many perspectives regarding what constitutes an optimal keyword density, most would agree that a rate somewhere between 1% and 5% is usually adequate. This means that a designated keyword will appear in an article one to five times for every one hundred words. If one is seeking a density of approximately 1.5% for a five hundred word article, the keyword should make seven or eight appearances.
Once you have your keyword chosen then you can simply use the search and replace feature of your word processor to start by replacing a keyword not of your choosing. Then simply add a few sentences here and there throughout your article that will complement your keyword preferences.