Before you can add your Linode credentials to Portainer, you will need to create an API token in your Linode account.
Creating your API token
Log into the Linode dashboard and click your account name in the top right. Select API Tokens. Click Create a Personal Access Token, give it a label and set an expiry. The Portainer provisioning functionality only requires Read/Write for the Kubernetes option, so disable the rest.
Adding your credentials
To add credentials for a Linode account, from the Shared credentials page click Add credentials, then select the Linode option. Give your credential set a name and paste your API key into the box.