Hi Guillermo,
If you are a Windows user, you might find our slides more detailed than the documentation (which sort of assumes you are a developer). Some of the AtoM commands are out of date (like how to restart PHP-FPM) so check our documentation for those, but the general configuration and use is still the same. Notice that we recommend starting the Vagrant environment from the command-line, and not directly from the VirtualBox interface. See:
Next, make sure your VirtualBox and Vagrant versions are recent. I have previously had problems when they weren't!
Also, by searching for label:vagrant label:FAQ in the user forum, I found a number of previous forum threads with some useful troubleshooting suggestions that might help you. For example, see:
And finally, if you are NOT on Windows, you might find the Docker development environment easier to use. See:
Good luck!