Sophos AV requires almost no interaction on your part. Its virus database is updated once an hour, automatically (laptop users are updated instantly when their computer gets a valid network connection).
If Sophos detects a virus you will see a dialog box pop up on your screen similar to the following:
As you can see in the example above, this particular file was just a standalone virus and Sophos automatically deleted it. If this was a file that was infected, you would have received a similar notice that the file has been disinfected. The only action you need to take is to click OK to confirm the message.
In addition, running "manual" scans is not necessary. Sophos is an "on access" scanner, which means whenever you or your computer access a file on your computer it is automatically scanned for the latest threats. Manual scans may uncover decades old emails attachments with viruses in .zip files or other irrelevant and ancient malware that cannot infect your computer and longer and thus manual scans are both misleading and unnecessary.