Howe to get API data using Bearer Access Token dynamically?

I figured this out myself, and detailing here for someone else who might need it.

First, get the Access Token and convert it into a table:

let
    Source = Json.Document(Web.Contents("api-to-get-access-token")),
    #"Converted to Table" = Record.ToTable(Source),
    #"Sorted Rows" = Table.Sort(#"Converted to Table",{{"Name", Order.Descending}}),
    #"Promoted Headers" = Table.PromoteHeaders(#"Sorted Rows", [PromoteAllScalars=true])
in
    #"Promoted Headers"

The sort rows and promote headers are just so I will have one row. The final result looks like this:

TABLE A:

Next, convert the original API call, which uses the access token value, into a function:

(token as text) =>
let
    Source = Csv.Document(Web.Contents("api-to-get-data", [Headers=[Authorization="Bearer " & token]]),[Delimiter=",", Encoding=65001, QuoteStyle=QuoteStyle.None]),
    #"Promoted Headers" = Table.PromoteHeaders(Source, [PromoteAllScalars=true])
in
    #"Promoted Headers"

Then, on the above TABLE A, invoke the custom function created (go to 'Add Column' tab on the menu, select 'Invoke Custom Function'), and select the newly created function, and select the value of the 'Bearer' column as the value to pass to the 'token'.

This will give you a new column, which you can expand to get the data.