When an Internet connection is present, the anti-virus updates every 30 minutes by default (this is the most optimal setting).
When required, you can change this setting by doing the following: right-click on the Dr.Web icon located in the bottom-right corner of the system tray. Then, in the context menu, select Tools → Settings and go to the Updating tab.
Alternatively, you can update the anti-virus manually by right-clicking on the Dr.Web icon in the bottom-right corner of the system tray, and then selecting Updating in the context menu.