Here is how you can Open a project saved on your local computer:
1. Click Open Project.
2. Click Browse Disk and go to your Explaindio software installation directory.For Windows the default installation directory is C:\Program Files (x86)\Explaindio 4
3. Locate the projects folder inside your installation directory.
4. (Don't get into the _Assets folders) Scroll down and you will find your project files. Select and Open the project files that which has an extension of .explaindio or .explaindio_zip.
Here is a step by step tutorial video on How To Open A Project File From Local Computer.