Go to System > Improved Sorting > Sorting Criteria.
You will see the list of configured sorting options. If list is empty, magento will use default sorting options.
Here you can change the order of the criteria visible to users and add/remove available options.
Once you add your first sorting criteria, extension will replace native magento sorting options and use your configuration.
Ranking Factor - internal functionality, that calculate product "weight" or "relevance"
- Name - name of option, visible in dropdown
- Is Default - if selected, sorting criteria will be applied by default on category page
- Is Default for Search - if selected, sorting criteria will be applied by default on search results page (instead sort by relevance)
- Position - position of sorting option in dropdown
- Conditions - describes logic to sort products. You can use catalog attributes and/or ranking factors. An attribute is visible for sorting, if option "Used for Sorting in Product Listing" is enabled (Stores / Attributes / Product)