Hello :)
Thank you for your purchase <3
Unfortunately, you can't open gdevelop projects directly from your phone storage, but there is an easy way to solve this:
1- Open GDevelop desktop app on PC or Laptop.
2- Unzip the template project and open the .json file in gdevelop.
3- Save the project in your cloud (make sure you are logged in into your account).
4- Close everything and open gdevelop from your mobile.
5- Now you can simply select and open the project from your cloud projects list.