Power Automate Desktop: Making API Calls?

Hello,

I am new to working with APIs but have managed to get a response as intended using Postman. However I am unable to get it to work with Power Automate Desktop.

HTTP > Invoke Web Service

There is a field for URL and method, but I also have the following keys and values that need to be added:

• method [VALUE]
• vendor_id [VALUE]
• client_key [VALUE]

I assumed these are entered into "Input / output variables" but vendor_id is an integer and the data type does not seem to allow me to change it.

Am I headed in the right direction??