to use the recommended videos on the google tv home, use voice search, and use the YouTube button some remotes have, you need the smarttube bridge app. unfortunately you need root or adb to perform this. adb can be done remotely on a pc if wireless debugging is enabled.

just open the settings -> system -> developer options -> enable wireless debugging.
then you can connect to the ip on screen on a pc using

adb connect <local ip address>

eg

adb connect 192.168.0.50

then uninstall the official app completely using:

• for root(?)

adb shell pm uninstall com.google.android.youtube.tv

• on adb

adb uninstall com.google.android.youtube.tv

then you can install the bridge app on smarttube under

• Settings -> About -> 'Enable global search'.

• Or you can install the bridge apk remotely by downloading it from here
  https://kutt.it/stn_bridge_atv and running

adb install ".\ATV_SYTV_Bridge.apk"

(you probably have to change the path)

• or using a downloader app (eg Downloader by AFTVnews)
  and entering

kutt.it/atv_bridge_atv