Extension-manager > Get preconfigured distribution.
Activate the distribution "Launch TYPO3 Responsive!" (launchstart).
Edit the Launch plaugin: select a valid user.
Start your TYPO3-frontend.
Click on [Launch your TYPO3-project!]
Launch TYPO3 Responsive! will check dependencies.
If a requirement missed you will get a prompt.
See Known Bugs
Please refer to the section Error Handling of the manual Launch it! (launch) at https://docs.typo3.org/p/netzmacher/launch/main/en-us/KnownBugs/
If link isn't proper, please refer to https://docs.typo3.org/typo3cms/extensions/launch and look for Error Handling.