For general searches type in one or more words in a field of your choice, e.g. 'Grant' in the 'Artist/Photographer/Maker' field.
If you know what you are looking for, narrow down the results using more than one field, e.g. a search for 'Grant' in the 'Artist/Photographer/Maker' field and 'bicycle' in the 'Image Title' field to find Henry Grant's 'Two boys riding a bicycle: 1973'.
When searching using more than one word the search brings back the closest matches first.