On the app, go first to the 'my progress' page then click on the 3 dots in top right hand corner and choose 'help and feedback'
from the 'help centre' page click on the 'menu' button and choose 'reviews' from the drop down menu. Once on the review page you will be able to add your own review.
Alternatively, you could log onto the website on your tablet and, although it won't recognise any voice input, it should have a 'review' tab along the top.
hope one of these methods works for you.