Hi @brsastre
glad for the feedback 
Just to let you know, the env file is auto-generated when using the CLI tool not cloning it down. (you want to use the CLI tool to create your project). The user here had cloned down their own repo meaning the .env would not exist as itโs not to be committed to github.
Could be explained in the documentation indeed, feel free to make a PR here GitHub - strapi/documentation: Strapi Documentation and add some 
Should also be explained some information regarding .env and the environmental variables in our documentation.