Either drag-and-drop an URL from a web browser or use the built-in search:
Can be considered as an example of C++/Qt <-> Python integration.
Sometimes it is needed to visit pytube issues list and apply fixes, for example
pip3 install --force-reinstall https://github.com/yt-dlp/yt-dlp/archive/refs/heads/master.zip
For Fedora:
sudo dnf install qt5-qtquickcontrols2-devel
sudo dnf install qt5-qtbase-private-devel
sudo dnf install qt5-linguist