1. after you download and install avira antivirus on your computer. then you need to update antivirus databases on a regular base, in order to identify the latest virus-virus.
Right-click on the icon avira (on the taskbar to the right below)
select the Start Update ...
2. If you want to update manually (offline) then you must have defenition file, you can copy the friends I already have the update file, or download directly on the site authorized.
you can download here
3. To start the update manually (offline)
On the menu bar select "Update -> Manual Update ..
4. Dialog box will appear as below
Find the folder / file that contains update antivirus
Then you will start antivirus updated
5. To download the installer Antivir, click here