Currently there's no package or port for VAST available, so you need to build VAST from source.
You can install most dependencies as binary packages:
We encountered issues with Arrow and CAF: VAST segfaults unless the binary
package were built using the exact same system compiler. The easiest fix is to
build the dependencies yourself. Since we bundle CAF as submodule, you can
--with-bundled-caf to our
configure wrapper script. Alternatively,
use the port
/usr/ports/devel/caf. For Arrow, we recommend using the port
/usr/ports/databases/arrow/ or build from source as fallback.
After all dependencies are in place, you can proceed to build VAST from source.