Tips for creating a digital library:
https://www.edutopia.org/article/how-create-digital-library-kids-eat
https://www.odilo.us/librarian/10-tips-to-build-a-perfect-digital-library-for-schools/
https://www.weareteachers.com/perfect-digital-libraries/
Some popular digital libraries in k-12:
https://www.commonsense.org/education/articles/the-best-digital-libraries-for-kids-and-students