This repository contains a Postman Collection and Environment which mirrors the NDFC REST API.
https://www.postman.com/downloads/
3b. In the import dialog, click on folders in the sentence "Or select files or folders" (or drag and drop the folder to the dialog)
4. Edit the imported Environment to match your local environment (e.g. ndfc_host, base_url, ndfc_username, ndfc_password, etc)
You should receive back a token from the NDFC controller which will last until the token times out, at which point you'll need to execute the Login request again.
At this point, the other REST endpoints should work (assuming you've edited the corresponding variables in the Environment)