How to calculate access_token for OAuth authorization?

Question

OAuth

I can't figure out OAuth authorization. There is such an access_token parameter. As I understand it, it is somehow calculated based on client_id and client_secret, right?
Here, for example, is the description for getting data from the Points bank:

POST /api/v1/statement HTTP/1.1
Host: enter.tochka.com
Accept: application/json
Content-Type: application/json
Authorization:Bearer
{
"account_code": "Account number",
"bank_code": "Bank BIC" ,
"date_end": "Statement end date, date format YYYY-MM-DD",
"date_start": "Statement start date, date format YYYY-MM-DD"
}

Answer 1

No. There are 2 types of tokens: by Reference and by Value. by Reference is a randomly generated value. by Value, this is usually JWT and they sign it mainly with asymmetric encryption (RS256 at least) and no one will tell you the private key, and you will never pick it up