Convert SQL to LINQ Query

Question

I need to use the following SQL query in LINQ, but despite my best efforts, I am unable to make it work.

This is the SQL command:

SELECT     ST.Description, ST.STId, COUNT(SI.SIId) AS Expr1
FROM         BP INNER JOIN
                      MbrBP ON BP.BPId = MbrBP.BPId INNER JOIN
                      SI ON BP.BPId = SI.BPId RIGHT OUTER JOIN
                      ST ON SI.STId = ST.STId
WHERE     (BP.CountryId = 1) AND (BP.RegionId = 1) AND (MbrBP.MemberId = 1)
      AND (SI.IsActive = 1)
GROUP BY ST.Description, ST.STId
UNION 
SELECT      ST.Description, ST.STId, COUNT(SI.STId) AS Expr1
FROM         SI RIGHT OUTER JOIN
                      ST ON SI.STId = ST.STId
GROUP BY ST.Description, ST.STId

Can someone please help me with this?