Joins On Subqueries - join

Question

I'm still kinda new to SQL; please spare me. I have an issue with trying to join a table or another view to my existing query below.
The last question I had asked refers to joining the two subqueries and giving them an alias in order for the join to work (something I still don't understand?) I'm trying to join a table and another subquery to the query below. But I'm not quite sure how I could continue adding subqueries to it.
I don't really understand how the alias names allowed the subqueries to be joined, and if I add another subquery, then I'll add another alias?
Any assistance you could provide would be much appreciated. Apologize in advanced for the formatting :/
Select
Sub4.DT as Date, Sub2.USOH, Sub2.USOHP, Sub2.OVXH, Sub2.OVXHP, Sub4.USOPP, Sub4.OVXPP
From
(Select
*
From
(Select
x.ID, x.Date, x.USOH, x.OVXH, convert(varchar, x.Date, 1) AS DT,
Abs(Cast((((x.USOH / NullIf((y.USOH), 0)) - 1) * 100) AS Decimal(10, 2))) AS USOHP2,
Format(Abs(((x.USOH / NullIf((y.USOH), 0))) - 1), 'P') AS USOHP,
Abs(Cast((((x.OVXH / NullIf((y.OVXH), 0)) - 1) * 100) AS Decimal(10, 2))) AS OVXHP2,
Format(Abs(((x.OVXH / NullIf((y.OVXH),0)))-1),'P') AS OVXHP
From
(Select
a.Date as aDate, Max(b.Date) As aPrevDate
From
MACDHistogram A
Inner Join
MACDHistogram b on a.Date > b.Date
Group By a.Date) Sub1 -- Group Date > Previous Date SUB1
Inner Join
MACDHistogram x on Sub1.aDate = x.Date
Inner Join
MACDHistogram y on Sub1.aPrevDate = y.Date) T2) Sub2 --Histogram Percent SubQuery SUB2
Inner Join
(Select
*
From
(Select
z.ID, z.ID2, z.Date, z.USO as USOP, z.OVX as OVXP,
convert(varchar, z.Date, 1) as DT,
Cast(((z.USO / NullIf((q.USO),0)- 1) * 100) as Decimal(10,2)) AS USOPP2,
Format(((z.USO / NullIf((q.USO),0))-1),'P') AS USOPP,
Cast(((z.OVX / NullIf((q.OVX),0)- 1) * 100) as Decimal(10,2)) AS OVXPP2,
Format(((z.OVX / NullIf((q.OVX),0))-1),'P') AS OVXPP
From
(Select
c.Date as cDate, Max(d.Date) As cPrevDate
From
Prices C
Inner Join
Prices d on c.Date > d.Date Group By c.Date) Sub3 -- Group Date > Previous Date SUB3
Inner Join
Prices z on Sub3.cDate = z.Date
Inner Join
Prices q on Sub3.cPrevDate = q.Date) T4) Sub4 -- Price Percent Subquery SUB4
On Sub2.Date = Sub4.Date
Order By
sub4.Date Desc