Welcome to TYPO3 Flow!
There are a few things you need to know to get started with TYPO3 Flow. All necessary steps are explained in the Getting Started tutorial.
In short here's what you need to do:
- Set up a virtual host for your web server and let it point to the Web/ directory of TYPO3 Flow.
- Adjust the file permissions. On Linux / Mac just run
sudo ./flow flow:core:setfilepermissions johndoe wwwuser wwwgroup
from TYPO3 Flow's main directory (replace the user names by some matching your system environment!). - Call the URL leading to your virtual host from a browser
Have fun!