Manual scan sensitivity is Quick, Standard and Thorough all of these you can select to also scan archive files or not (the default is not to scan archives). You can choose to either scan Local Disks (all hard drives), Folder Selection (just a particular, folder or partition, etc.) or Removable Media.
As Igor says, what is it you are trying to achieve ?
Have you checked the avast help file, Simple User Interface, Working with avast! 4 in the Simple User Interface ?