I contacted our technical support here at school and this is the resources they recommended for text to speech support. I'm sure you will have to play with some of this, that is the kids, they are better at this than adults! Let me know if you find these resources helpful or not.
For Chromebooks that you checked out from school:
Click on the battery icon in the lower right.
A window will open, click on accessibility.
Click on ChromeVox.
I also had to go to the gear at the top right and click on it.
Under "speak text under the mouse" toggle it to the right. This moves a box around on the page and what is in the box is spoken.
You may need to this on and off as needed because it will read everyting on the page constantly!
Read Aloud is the most used and recommended narration extension of that type but ither shoul be easy to use for your purposes.
Following these links will take you to the installation page.