How do I livestream from Teradek Vidiu via Nimble Streamer?

Teradewk Vidiu: Transport protocol: RTMP

A step-by-step guide would be much appreciated because I am not an expert in online video streaming.

Thank you

Hello.
I'm not an expert in Teradek VidiU too.
So please find this quick start guide for Teradek VidiU:
http://www.streamingstore.com/store/documents/vidiu-quick-guide.pdf
Go through this guide to the chapter 5(d):
In the Broadcast section click on “platform” to configure the details of your streaming provider. Four presets offer fast access to: Livestream, Ustream, YouTube, or “Custom”. Select one of the 3 providers, or select “Custom” and type your RTMP media server URL, stream name, and login credentials.

At this point you need to:
1. select "Custom"
2. specify your Nimble Streamer IP address (or URL) with your application name and your stream name (for example, 5.100.94.102/live/stream).

You need to configure your Nimble Streamer server:
1. create application (e.g. live) with push login and push password
2. Add RTMP interface with port 1935 (RTMP standard port).
3. Check the checkboxes for protocols your are want to transmux your incoming RTMP stream in your steaming application.

Please read this article for detail:
http://blog.wmspanel.com/2014/06/rtmp-hls-transmuxing.html