When you select elements on a page, kimono will generate the extraction rules associated with the elements. You can get more targeted by clicking and dragging over the data you want (rather than just clicking). In advanced mode you can directly edit the CSS selectors, and attributes extracted, resulting in a finer level of control over what data is retrieved.
During API creation, these advanced features can be accessed via the data model view , by clicking the 'Advanced' link
The best way to use advanced mode is to first make some selections near the elements you want to extract. From here you can use advanced mode to modify the existing rules to select your data rather than creating the selectors from scratch.
Advanced mode can be helpful for selecting unclickable data on the page, changing the data model (association amongst your data types), broadening or tightening your CSS selectors to get the data you want and extracting attributes with kimono.
There are many other reasons why you might want to use advanced mode - for example to extract hidden data or to grab the pagination selector if you keep accidentally clicking it when trying to select it. The more you create with kimono, the more you'll lean on advanced mode to handle your frustrating edge cases.
We're always trying to improve the feature, so don't hesitate to shoot us a feature request if you encounter something you just can't solve with our current toolkit.