How to find first weekday in the month in MSSQL

declare @n datetime = dateadd(mm,0,getDate())

   declare @FirstWeekDayOfMonth int

   SELECT @FirstWeekDayOfMonth= CASE

         WHEN Datename(dw, Dateadd(dd, -Datepart(dd, @n) + 1, @n)) = 'Saturday' THEN Day(Dateadd(dd, -Datepart(dd, @n) + 3, @n))

         WHEN Datename(dw, Dateadd(dd, -Datepart(dd, @n) + 1, @n)) = 'Sunday' THEN Day(Dateadd(dd, -Datepart(dd, @n) + 2, @n))

         ELSE Day(Dateadd(dd, -Datepart(dd, @n) + 1, @n))

       END 

   select @FirstWeekDayOfMonth

Note: to find out first day of next month , change  first line to dateadd(mm,1,getDate()) 

1st day of next N month , change the first line to dateadd(mm,n,getDate())