I am plant one watch tower in wall compound then there is no entry no road I can change this place..

There are 2 methods:

1. After placing the building it will appear a round road-icon on top if it has no connection to roads. Click on that icon and the system will suggest what roads to build by default (if you confirm).

Or:

Click on the round "Build" icon on the bottom right side of your screen (hammer beneath Helmet).

2. Click on placed building (below that round icon on top) and hold for about 2 seconds. The building will be activated and 2 round icons will appear below (red "X" and green "check-symbol). Now you can move that building around to the place where you want it to be (where e.g. it has connections to some roads.