[SalesForce] What’s the definition of these ID’s stand for in Marketing cloud

Sounds like you need to designate an API user:

1. Admin
2. My Users
3. click on the user's name
4. Edit
5. check the API user checkbox
6. Save

Once the user has been designated, you can assign API permissions:

1. Admin
2. My Users
3. check the box next to the user
4. Manage Roles in the toolbar
5. Edit Permissions
6. Email
7. Admin
8. API Access
9. WebService API
10. check the box next to Allow

Here are the steps for installing a package and configuring a Client ID and Client Secret to authenticate your REST API calls:

1. Log into Marketing Cloud
2. Hover over your user name in the upper right corner
3. Click Administration
4. In the Account drop-down, click Installed Packages
5. Click the New button in the upper right corner
6. Give your package a name and click Save
7. Click the Add Component button at the bottom
8. Choose API Integration
9. Click Next
10. Check the permissions appropriate for your use-case. Typically you would check all options in Channels > Email and all in Data > Data Extensions.
11. Click Save
12. The Client ID and Client Secret are now configured and ready to use in your application.
13. Use the REST API tool of choice to request an Access Token for authentication. Once you have a token, you're ready to interact with the SFMC objects.

For authorizations, the endpoint is https://auth.exacttargetapis.com.

Once everything's configured, try requesting a token:

POST https://auth.exacttargetapis.com/v1/requestToken
Content-Type: application/json
{
    "clientId": "YOUR_CLIENT_ID_FROM_APP_CENTER",
    "clientSecret": "YOUR_CLIENT_SECRET_FROM_APP_CENTER"
}

The endpoint for all of the other SFMC REST API calls is https://www.exacttargetapis.com/.