In the 'Search for an answer' tab you type the search string into the textbox and then depending on how you want to search you press one of the following buttons:
Search / Change category: This option searches the knowledgebase and changes category to the selected category.
Google web: This searches the entire web with the Google search engine.
Google Directory: This option is used to search only sites in the specified category with Google.
Glubase - External links