In SQL SSMS I am trying to write a query following these instructions:

Youve been asked to send thank you gifts to customers who have purchased large quantities of your recently released chocolate animal series (stock item ids 222, 223, 224, 225). Your query needs to list the customer ID, the customer Name, have a column that totals units of each animal type, and a grand total for all animals. To qualify for the gift, the customer must have purchased at least 300 of any given animal type, or a total of 500 across all animal types. Your final query should sort by the total largest to smallest. You should get 20 rows the first two look like this -

CustomerID	CustomerName	Beetles	Echidnas	Frogs	Sharks	Total
441	Wingtip Toys (Keosauqua, IA)	216	432	0	96	744
573	Wingtip Toys (Marin City, CA)	264	0	312	168	744

This is my query so far.

SELECT SC.CustomerID, CustomerName, SUM(CASE WHEN WSI.StockItemID = 222 THEN (Quantity * -1) ELSE 0 END) AS Beetles, SUM(CASE WHEN WSI.StockItemID = 223 THEN (Quantity * -1) ELSE 0 END) AS Echidnas, SUM(CASE WHEN WSI.StockItemID = 224 THEN (Quantity * -1) ELSE 0 END) AS Frogs, SUM(CASE WHEN WSI.StockItemID = 225 THEN (Quantity * -1) ELSE 0 END) AS Sharks

FROM Sales.Customers SC INNER JOIN Warehouse.StockItemTransactions WSIT ON SC.CustomerID = WSIT.CustomerID INNER JOIN Warehouse.StockItems WSI ON WSIT.StockItemID = WSI.StockItemID

WHERE WSI.StockItemID = 222 OR WSI.StockItemID = 223 OR WSI.StockItemID = 224 OR WSI.StockItemID = 225

GROUP BY SC.CustomerID, CustomerName, WSI.StockItemID

ORDER BY CustomerName DESC

I can't figure out how to do the total, how to add the three values in each and how to only show the lines that are high enough values. Here are a few lines of the results I am getting right now just to illustrate.

549 Wingtip Toys (Lake Ronkonkoma, NY) 0.000 96.000 0.000 0.000 441 Wingtip Toys (Keosauqua, IA) 216.000 0.000 0.000 0.000 441 Wingtip Toys (Keosauqua, IA) 0.000 432.000 0.000 0.000 441 Wingtip Toys (Keosauqua, IA) 0.000 0.000 0.000 96.000 488 Wingtip Toys (Isabela, PR) 0.000 0.000 0.000 120.000 548 Wingtip Toys (Indian Creek, IL) 0.000 192.000 0.000 0.000

I need you to help me fix this query