Home base on fire, how to put fire out?

The fire will go out on its own after 30 minutes, but you may need to repair damage to your walls to make sure you keep your defenses up.

Tap on your Garrison Building and choose the Defense option. You will see a number for your City Defense and if it is below the max amount you will have the option to 'Restore city defense'. You can restore 80 points every 30 minutes.