To unlock Night Raids, your HQ must be at least level 4. Build the new Scout Tower, then tap Defend on the Tower to open the Night Raids menu. Then, use the Scout Tower to trigger Heroic Defense missions twice a day for Supply Crate Rewards.
Base Layout Tool
Tap "Layout Mode" to reorganize your Base quickly and more efficiently! Use the "Stash All" button to move everything into the tray, or tap "Quick Stash" to move individual buildings into the tray.