First go on the TeamSpeak website in the "Downloads" section.
Then Click the "Download" button next to "Client 32-Bit 3.0.0-betax
"x is the beta version.
Beta versions download all the time, so please keep an eye on that site.
Download the version for your operating system. In the example above i showed 32 bit to download.
If you have 64 bit operating system, then download the 64 bit version
Finaly Click "I agree" link on the very bottom of the end user agreement (EULA).
Once its downloaded, install it.
(No special settings are needed during the installation.)