You can enter the URL yourself after selecting the appropriate option in the browser. In Netscape this is the Location bar and in Explorer it is the Address bar at the top of the screen. None of these programs searches all the computers in the world, so the results you get will vary. The programs contain searchable indexes which are compiled by the program itself doing automatic regular scans around the Internet. Your search will be on the latest update of the index.
Some programs scan the titles of files, and some scan the contents of files for significant words.
Some scan only computers that have their files organised with certain software. You will retrieve a list of resources with links to them. A regularly updated catalogue of subjects with links to resources is maintained on the Bulletin Board for Libraries. Click twice on the name of the browser among the University of Westminster services offered, until an hour-glass appears, then wait for the connection. Click once on links or on icons within the browser.