Diluted EPS asks what earnings per share would be if securities that could become common stock actually did. These include stock options, restricted stock units, warrants, convertible notes and convertible preferred stock. The share count in the denominator goes up, and sometimes the profit in the numerator is adjusted too, for example by adding back interest on a convertible note that would no longer be owed.
Accounting rules set the methods. The treasury stock method is used for options and warrants and counts only the net new shares after assuming that the exercise proceeds are used to buy back stock. The if-converted method is used for convertible securities. Securities that would increase EPS, called anti-dilutive, are left out.
For a company that has a net loss, diluted EPS is generally the same as basic EPS, because adding shares would make the loss per share smaller, which is anti-dilutive.
Compare the diluted figure with basic EPS to see how much potential dilution there is, and read the note listing the securities that were excluded.