Locking up troops/Keeping troops behind walls

- Click on general headquarters

- Click on defencive tactics (where you set whether or not troops are behind walls or not)

- You'll see three options in red:

   1. Counter-plunder battle (for when someone plunders you)

   2. Defence battle

   3. Counter-scout battle

- Underneath each troop click the red flags to wall. Do this for all

   three if you have lots of scouts only the first two

- To the right you'll see a list of your cities

- Click on your cities (in the green circle)

- Click 'Apply current tactics to selected city'

- Click OK

And you're done...