Using the (Edit > Replace) dialog box

The (Edit > Replace) dialog box is almost identical to the (Edit > Find) except that it allows you to substitute one text string for another.

This dialog box lets you not only find text but lets you replace it something else.
You can also display this dialog box using the shortcut key (Ctrl + H).

Find Next - To find the next occurrence of the same text press Enter or click the Find Next button
Replace All - This will replace all instances of the text string.
Match Case - If the right mix of uppercase and lowercase letters is important check the Match Case check box before beginning your search.
Find Whole words - This is useful when you want to find some text that appears as a whole word.

You can press (Ctrl + Home) to go to the beginning of the presentation.