Dears,
As I understood from the details it is only a design job, as you need to have also an app developer to implement everything to the final working output, I will provide you the full screens of all the application for both entities and volunteers, also screens for the admins.
I have been working as web designer for more than 15 years passing through all UI techniques and methods.
It would be an honor to work for your project and provide you with the best results.
Thanks in advance