Since KF6 is not going to be released for another few months minimum, you might have trouble sourcing the libraries.
### Arch Linux
You have the set of -git packages for the dependencies used, such as `kirigami2-git`. Otherwise, build from source.
### Fedora Linux
Fedora's KDE SIG has a repository for KDE Frameworks and Plasma 6 [located here](https://copr.fedorainfracloud.org/coprs/g/kdesig/kde-nightly-qt6/). I use this in my own personal [COPR](https://copr.fedorainfracloud.org/coprs/redstrate/personal/) which builds Astra from git.
The most time-consuming option but the one that will definitely work is building the required frameworks from source. See the [page on the KDE Community Wiki](https://community.kde.org/Get_Involved/development/Build_software_with_kdesrc-build) on how to build KDE software yourself. Then, when building Astra feed the kdesrc-build usr directory, and it will pick up on these libraries automatically: `-DCMAKE_PREFIX_PATH=/home/<username>/kde/usr`.
Remember that unless you're running in a kdesrc-build session you need to set some environment variables otherwise Astra will fail to run (because it fails to find some runtime KF6 dependencies). Make sure to `source prefix.sh` from the build directory, or from another kdesrc-build project.
**Note:** Some dependencies will automatically be downloaded from the Internet if not found on your system. This functionality may change in the future.
When configuring Astra, there are several optional features you may want to enable or disable: