Convert SQL to LINQ with multiple types of joins

I need to convert a SQL query into LINQ, either to Query Syntax or Method Syntax.

SELECT
	IA.ItemId,
	IVT.ItemName,
	C.DeliveryMethod,
	SUM(OD.Quantity) AS Qty
FROM OrderHeader OH
     INNER JOIN OrderDetail OD ON OH.OrderId = OD.OrderId
     LEFT JOIN Customer C ON OH.CustomerId = C.Id
     LEFT JOIN ItemAvailability IA ON OD.ItemId = IA.RecId
     INNER JOIN Inventory IVT ON IA.ItemId = IVT.ItemId
WHERE OH.DeliveryDate = '02/03/2023'
  AND OH.OrderType = 'Web'
GROUP BY IA.ItemId, Ivt.ItemName, C.DlvMode
ORDER BY IA.ItemId

I've spent a long time Googling and YouTubing, but everyone provides examples of either just Inner Joins, Group Joins, or Left Joins. No one gave example of having both Inner Joins and Left Joins in the same query.

I know the syntax for a simple inner join like this:

SQL

SELECT     OH.OrderId, OD.ItemId, OD.Quantity
FROM       OrderHeader OH
INNER JOIN OrderDetail OD ON OH.OrderId = OD.OrderId
ORDER BY   OD.ItemId

LINQ

from oh in OrderHeader
join od in OrderDetail on oh.OrderId equals od.OrderId
orderby ordt.IItemId
select new {
    OrderId = oh.OrderId,
    ItemId = od.ItemId,
    Quantity = od.Quantity
}

And I know the LINQ syntax for left join also. But I am having trouble to figure out how to have both inner and left joins in one LINQ query.

I hope someone here can help, please.

Just combine join techniques together

var deliveryDate = ...;

var query = 
    from oh in OrderHeader
    join od in OrderDetail on oh.OrderId equals od.OrderId

    join c in Customer ON oh.CustomerId equals c.Id into cj
    from c in cj.DefaultIfEmpty()

    join ia in ItemAvailability on od.ItemId equals ia.RecId into iaj
    from ia in iaj.DefaultIfEmpty()

    join ivt in Inventory on ia.ItemId equals ivt.ItemId
    where oh.DeliveryDate == deliveryDate && oh.OrderType == "Web"
    group od by new { ia.ItemId, ivt.ItemName, c.DlvMode, c.DeliveryMethod } into g
    select new 
    {
        g.Key.ItemId,
        g.Key.DeliveryMethod,
        Qty = g.Sum(x => x.Quantity)
    } into s
    orderby s.ItemId
    select s;