Query to find the 'Branch_Code' of the 'Channel_Num' with the lowest 'Issue_Date' using T-SQL Hope you're doing well

I have a table with the structure below :

Customer_Channel_Branch:(Customer_Num int ,Channel_Num int ,Branch_Code int ,Issue_date  datetime)


Some Example Data :

                  "Customer_Channel_Branch"
---------------------------------------------------------
Customer_Num     Channel_Num    Branch_Code    Issue_date  
    x                 1             1000         1990
    x                 2             2000         1991
    x                 3             3000         2000


There is another table with this structure below:

 Channel_general_Code:(Channel_Num  int , Channel_gnrl_Code  int)


some example data for this table:

            "Channel_general_Code"
-------------------------------------------
     Channel_Num     Channel_gnrl_Code
        1                 1
        2                 1
        3                 1


As you can see in the second table , all three Channel_Num --&gt; (1,2,3) are grouped as one single channel . So what I want in the result set is this :

                    "result"
----------------------------------------------
Customer_Num     Channel_Num     Branch_Code
    x               1               1000           
    x               2               1000
    x               3               1000


for Channel_Nums that are considered as one , (have the same Channel_gnrl_Code in the second table), I need the Branch_Code of the Channel_Num with lowest Issue_date.
I thought that I could use window functions 

(`row_number() over(partition by Channel_gnrl_Code order  by Issue_date )`)


to write this query but it gave me a false result.
I was wondering if you could help me with this.

Thanks in advance
Avoid Row_Number because first it process whole table then again you select row
where rn=1 for each group

DECLARE @Customer_Channel_Branch TABLE (
    Customer_Num VARCHAR(10)
    ,Channel_Num INT
    ,Branch_Code INT
    ,Issue_date INT
    )

INSERT INTO @Customer_Channel_Branch
VALUES (
    'x'
    ,1
    ,1000
    ,1990
    )
    ,(
    'x'
    ,2
    ,2000
    ,1991
    )
    ,(
    'x'
    ,3
    ,3000
    ,2000
    )

DECLARE @Channel_general_Code TABLE (
    Channel_Num INT
    ,Channel_gnrl_Code INT
    )

INSERT INTO @Channel_general_Code
VALUES (
    1
    ,1
    )
    ,(
    2
    ,1
    )
    ,(
    3
    ,1
    );

WITH CTE
AS (
    SELECT a.*
        ,b.Channel_gnrl_Code
    FROM @Customer_Channel_Branch A
    INNER JOIN @Channel_general_Code B ON a.Channel_Num = b.Channel_Num
    )
SELECT c.Customer_Num
    ,c.Channel_Num
    ,ca.Branch_Code
FROM CTE C
CROSS APPLY (
    SELECT TOP 1 Branch_Code
    FROM CTE C1
    WHERE c.Customer_Num = c1.Customer_Num
        AND c.Channel_gnrl_Code = c1.Channel_gnrl_Code
    ORDER BY c.Issue_date
    ) ca