Another way to build new roads is to use the pave mode in your mobile app. Use the reports button. In some countries, there will be a large button with a picture of a yellow tractor. In other countries, choose "map issue" and then "Pave" and follow the instructions. As soon as you get far enough away from a known road, Waze will start recording your movement as new road segments, with junctions (nodes) at your turns. When Waze detects that you are back on a known road, road building mode is automatically paused.
Please turn off road building mode when it is not needed to prevent duplicate roads being recorded in case of GPS errors on your mobile device or errors downloading parts of map due to poor cellular phone coverage.
When you are done, wait until the road turns red on your screen before turning off paving mode to make sure the final segment is saved. If you have accidentally started to record a road in error, you can quickly turn off pave mode before it is saved.