Prerequisites: Create a API Role, a dedicated API User and Launchpoint service, see related Marketo Documentation.
Recommended REST API Settings : Access API (All rights)
Minimal REST API Settings (this may change over time as we add new features): Access API, Execute Campaign, Read-Only Campaign, Read-Write Assets and Approve Assets.
Where do I find my Marketo REST API information?
In Marketo Admin section look for Web Services section to access REST Endpoint. Access the Launchpoint Service section, and collect your Client ID and Client Secret.
Watch this short Video for a quick walk-through.
Ok that was as technical as it can get. Now let's go to the fun part.