The easiest way is to create your text using Microsoft Word by either writing or pasting to it. Then make sure you save the document but instead of saving as a .DOCX file you need to change the format to a .TXT file.

Creating Text-to-Speech audio from a text file1

Click the File menu in the Tutor Player (not the Tutor software!) and select the Open option.

Browse for the saved text (.TXT) file and then select Open. You will then see the message below.

Creating Text-to-Speech audio from a text file2

Click Yes and then follow the same 5 steps as described in the article Using text-to-speech as part of an activity.  The only difference is that the file is not launched to the students so you will need to add it to the playlist before or during the lesson.