Answer for a) from the Vagrant homepage:
"Once you or someone else creates a single Vagrantfile, you just need to vagrant up and everything is installed and configured for you to work".
Open a new terminal window and enter
sudo vagrant up
Wait, until the line
--> default: flag to force provisioning...will still run.
Then you can open FireFox inside your Ubuntu and use the following local IP:
or you can use the given IP-Address to your VM Ethernet adapter as you can find it with the command
In my case, it is
which should be available from every PC in your LAN, not only inside the VM.
To stop your local MusicBrainz-Server enter:
sudo vagrant halt
We still have to wait for a working local search server and local (re)index scripts.