---
schema_version: "1"
id: a6f1f4c82f8192eb39560e256e1a5a74d27299eda691b0219825c83c2964cc59
title: Set Up Your Development Environment for Legacy Packages
collection: developer
version: current
locale: en-us
portal_url: https://docs.salesforce.com/developer/current/en-us/marketing-cloud/guides/mc-getting-started/mc-dev-setup.md
canonical_url: https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/mc-dev-setup.html
source_site: developer.salesforce.com
content_type: documentation
content_hash: 074d9fccebabafb7e69e0392e4dfa50021858e5b3a1fa15714763bf7afbb2e38
products:
  - Marketing Cloud Engagement APIs and Programmatic Languages
  - Marketing Cloud
---
# Set Up Your Development Environment for Legacy Packages

1.  [Install a Package](https://developer.salesforce.com/docs/marketing/marketing-cloud/mc-app-development/install-packages.md) To create API integrations, install custom apps, or add custom Journey Builder components, create an installed package.
2.  [Get a Client ID and Secret](https://developer.salesforce.com/docs/marketing/marketing-cloud/mc-app-development/api-integration.md) To use an API, create an API integration. Creating an API integration gets you a client ID and secret.
3.  [Get an Access Token](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/get-access-token.md) Use your client ID and secret credentials to get an OAuth access token directly from the requestToken API authentication service. Use the access token to authenticate subsequent calls.

## Related Items

- [requestToken Reference](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/requestToken.md)
- [Packages](https://developer.salesforce.com/docs/marketing/marketing-cloud/mc-app-development/packages-overview.md)
- [Manage Licensing for Installed Packages](https://developer.salesforce.com/docs/marketing/marketing-cloud/mc-app-development/license-installed-packages.md)