The model_id identifies your model to numerai. Model name is to model_id what hostname is to IP address.
In Python, I do this:
import numerapi
napi = numerapi.NumerAPI(public_id=public_id, secret_key=secret_key)
napi.upload_predictions(path_to_predictions, model_id=model_id)
I get public_id from https://numer.ai/account, upon clicking the VIEW API KEYS button. secret_key was shown once when I created my webhook. I assume you have to destroy and recreate the submit webhook to get a new secret key. (In practice I store these things in Google Cloud Secret Manager.)
model_id is the UUID for your model which is obtained from https://numer.ai/models.
To manage your stake, use
napi.stake_increase(nmr=nmr_amount, model_id=model_id)
napi.stake_decrease(nmr=nmr_amount, model_id=model_id)
I don’t know how to delete a pending stake change using the API.