You need a special browser bundle for it, which you can get here: https://www.torproject.org/projects/obfsproxy.html.en They are listed under "Download the Pluggable Transports Tor Browser Bundle". These special bundles will become the regular browser bundle in a few weeks (they are still experimental). Then go here: https://bridges.torproject.org/bridges Copy the "obfs3 <IP address>:<Port>" lines and add them in Onion Icon -> Settings -> Network -> My ISP blocks connections to the Tor network -> Add a bridge.