Let's walk through the features of the Advanced Search form.
In Advanced Search, the default location on "Search for" is "Everything" (i.e., all physical and electronic resources) and the default search filters are "Any field" and "Contains." On the right side of the form, the defaults are set to all material types in any language, with no date limits. The defaults enable you to cast a wide net and (in theory) retrieve a greater number of search results.
Changing the defaults will allow you to construct different types of searches, which may retrieve fewer but more relevant results.
Below is the Advanced Search form, with its featured labelled by number along with corresponding descriptions.

These appear in a row at the top of the Advanced Search form. The default location on "Search for" is "Everything" (i.e., all physical and electronic resources). If you want to search only for physical items that are in the UK Library Catalog, select the "Library Catalog" button. You can also limit to items held in Course Reserves, Local Collections, or WorldCat.
The first drop-down box (2a) allows you to choose which part of the item record you want InfoKat to search.
The second drop-down box (2b) combines the search location with your search terms.
Type in what you're looking for!
If you're constructing a complex search, add additional terms to the identical box in the second line.
The second line begins with a drop-down box (4a) that contains options for linking your search rows together. The terms in this box are called Boolean operators and help create internal logic for the search.
The second and third drop-down boxes (4b & 4c) in the second line are the same as those in the first.
If you're constructing a very complex search, you may wish to add additional lines to your search. Click this button to add them one by one. Use the drop-down boxes to pick the best options for linking the lines together.
Limits allow you to narrow your results by certain characteristics that you specify. These appear on the right side of the Advanced Search form and there are several to choose from.