Tokyo Station to Nasusiobara station

I will be traveling from the Tokyo station to the Nasusiobara station by the Shinkansen line. I am having difficulty determining which exact train to take, which color, and which number. I have never been in the Tokyo station and need the platform number also. Any help would be deeply appreciated. Thank you.

Take the Tohoku Shinkansen to Nasushiobara Station from Tokyo Station. Multiple different train names go there.
When you purchase your ticket or get a seat reservation the signs or on the seat reservation will tell you exactly which platform it is.

You can check timetables:
www.hyperdia.com or http://www.jorudan.co.jp/english/norikae/

Correction, the signs on the platforms and in the station (not the ticket) will tell you exactly where the train will be departing next. Use the timetables to determine which train you might want to take.