Tap the icon at the bottom of the broadcast screen.
Select either Share Live (or Share From Beginning, if in replay mode), or Share From (insert timestamp). In the first option, the video will start to play live (or from the beginning, if in replay mode). In the second option, the broadcast will start to play at the exact part you select.
You can tap and hold to scrub forwards and backwards, to choose the exact part you want to share. When choosing a section to share, keep in mind that only the previous two minutes of the broadcast can be shared. For example, if you select a moment 12 minutes into a broadcast, you can share it starting at the 10 minute mark and ending at 12 minutes.
Select who you want to share the broadcast with. You can choose to share to All Followers, Specific Followers, Twitter, or Share Link.
Tapping All Followers will share the broadcast with all of your Periscope followers automatically.
Choosing Share Link will pull up a menu from which you can select where you want to share the link. You will be able to share the link to select apps on your device or you can tap Copy to share the link outside of the Periscope app.
If you select Specific Followers, you will be prompted to select which Groups or Mutuals you would like to share the broadcast with. If you choose Twitter, you will have the option to edit your Tweet before tapping Tweet.