Step Two: click the Post Button to bring up your posting options

Once you click Post, you should the option to Go LIVE

This is what it looks like on my Samsung Galaxy

You will see the Go Live Button at the bottom ( your phone may be slightly different based on your operating system and type of phone. the little red icon with a person's head in the middle seems to be universal on all devices I have seen.

Step Three: click on that red Go Live Button Link