Go to https://pusher.com/ and create an account if you don't have one yet, then login and go to the main dashboard.
On the left panel select "Channels apps" and select an application, create one if you don't have one already.
Click on the "Getting Started" section.
Copy the key from the line that looks like this:
Go to instadeq, open an existing visualization or create a new one. In the Source section select the Pusher type.
Paste the key in the Key field, change the cluster value if needed.
Enter your Channel and Event names, you can leave the defaults if you are just trying it.
Click the green button and go to the Data section.
Now you can send data using the API following the instructions on the right panel.
You can also send data going to the "Debug Console" section in the Pusher dashboard and selecting the "Show event creator" button, enter the right channel and event if you changed them, you can change the JSON value to be sent, click "Send event" and check in instadeq if the data arrived.