Let's Read is a digital library initiated by the Asia Foundation. The library consists of over 2,000 books in 23 languages, the majority of which are in English and Khmer. Those books of high quality are available online here https://reader.letsreadasia.org/ and you and your school can make use of the children's storybooks in any way benefiting your students. From the website, your students can read and download those books for FREE. If you and your school have digital devices with Android system, you can also download an application from Google Play Store (Let's Read Digital Library) so that your students can easily read. Below are links to English and Khmer books.
Below is the link to two videos of how to download the app from Google Play Store and how to add the website on IOS Device's Homescreen.