Make sure to install ports and cvsup. Then run ports -u to populate the /usr/ports tree. To install a package go to the correct dir in /usr/ports and give the command pkgmk -d -i , which will first download the source, compile it and install.
Crux uses the X.org instead of XFree86. To configure X run xorgconfig.
To get ALSA sound running install the alsa-lib, alsa-oss and alsa-utils packages. For TeamSpeak to work set the following bars to max: "Master Digital", "PCM", "Synth", "Capture" and "Capture Boost". Enable capture for "Mic", and unmute "Master Digital", "PCM" and "Synth". As root run "alsactl store" to save the sound settings. They may be restored by running "alsactl restore", preferably from a script.
Create an audio-group for users that shall be able to play sounds, and then add "REGISTER sound/.* PERMISSIONS root.audio rw-rw----" to /etc/devfsd.conf.