Hi All,
I was able to succesfully get the access token and make calls to see my 2 records which i had attached.
Using the below calls for my instance i am able to see the attributes, contentDocumentLink, id, LinkedEntityID and ContentDocumentID, VersionData as well.

What steps should i do next to make call to see my document content/download my file?

Postman Call:
/services/data/v43.0/query?q=select id, LinkedEntityId,ContentDocumentId from ContentDocumentLink where LinkedEntityId = '0016asdasd33'

Postman call to get version data:
/services/data/v43.0/query?q=SELECT VersionData FROM ContentVersion WHERE (ContentDocumentId = '069sdsds' or ContentDocumentId = '069asdssd') AND IsLatest = true