Tokyo station, departing via shinkansen isn't too bad (as arriving at Tokyo station and trying to find the right exit)

This map should help, just look out for the signs for "tokaido shinkansen" - you can review the 1floor map. Yaesu (bottom off map) is the east side and has direct access, marunoichi (top) is west side requiring a little walk

If you're on the "wrong " side, just enter the ticketed area (pink area on map) and head towards the dark pink on map (you can't miss the large shinkansen signs, they are very well labelled)

Map: https://www.jreast.co.jp/e/stations/e1039.html

​​​​​​ shinkansen sign: https://commons.m.wikimedia.org/wiki...d_20090212.jpg

more signs: https://mithunonthe.net/2015/10/08/j...e-tokyo-kyoto/