I have no fields available for sorting with Search API sorts module This question is similar to another question I had, but now in a different context.  My previous question was: Search text box for Search API + Database + Search Views + Facets API + Facets Bonus

That option worked, except I can't use Current Search to reset the search box.  I can reset the filters, but not search box.  I also can't find an option to allow the user to sort the fields.  I installed the Search API Sort module, but was unable to get any fields to be available.  I kept hosing my index trying to enable/disable fields, and couldn't figure it out.

My question is how can I use a search form box with Search API + Views that will let me reset the search box with Current Search box, and, how can I have a sort box that will let the visitor select the field to sort by?

My view is rendering nodes via Display Suite view modes.  Right now, I am using exposed search and sort filters, but of course, they are grouped in one block.  The whole point of my having to use the Search API was to provide filters and decouple my search and sort filters from each other.  My sort option will be placed at the top right of the UI, and the sort in the left sidebar.

EDIT: Using Search API Sorts, per giga's advice below, I went back and tried to get my fields sortable.  I stripped down fields and still no luck getting them sortable.  It's a Commerce site, and I'm using the Commerce Search API, which gives me a Product Display index.  I originally move fields of content out of the index, so I'm only left with my product display and product fields.

My indexed fields right now are (field, type, boost):

Content type -- String -- 1.0
 Title -- String -- 1.0
 Date created -- Date -- 1.0
 Date changed -- Date -- 1.0
 Product Tags -- Taxonomy term
 Product Ref -- Commerce Product
 Item Type -- Taxonomy term
 Weight Sort -- Integer -- 1.0
 Product Ref >> Price >> Amount (decimal)(Min) -- Decimal -- 1.0
 Product Ref >> Price >> Amount (decimal)(Max) -- Decimal -- 1.0
 Title (Fulltext)  [search_api_aggregation_1] -- Fulltext -- 1.0
 Product Tags (Fulltext) [search_api_aggregation_4] -- Fulltext - 1.0
 Item Type name (Fulltext) [search_api_aggregation_5] -- Fulltext - 1.0
 Product tags >> Name -- String -- 1.0
 Proudct Ref >> Serving Size -- String -- 1.0
 Product Ref >> Portion Size -- Fulltext -- 1.0
 Item Type >> Name -- String -- 1.0
 Product Ref >> Price >> Amount (decimal) -- Decimal -- 1.0  

The only fields I'm trying to index are Title, Min and Max price, and the Weight Sort as the initial default sort.  None of them are showing up in my table of sortable fields under the Sorts tab.
Search API Sorts only lists the fields of supported types. Make sure the fields you want to sort on are single value strings or numbers.

If the fields are mutli-value you can use Search API Ranges‎ to give you max/min value fields that you can use.

If a field is full-text, one trick is to create an aggregated field containing just that field and assign it a string type.