cURL - to test web APIs with the POST method from a terminal

What exactly is your question here?

I am trying to build a connection between appian and Jenkins for testing purpose. So for that according to this document https://docs.appian.com/suite/help/20.4/Running_Automated_Tests_on_Expression_Rules_with_Jenkins.html 
I have created some sample test webAPIs, Now I want to test them. 
Document is saying "To test web APIs with the POST method from a terminal, try the following cURL command: curl - X POST -u [username]:[password] https://[Appian Site]/suite/webapi/[startTest API]"

I dont know what does terminal means here ? 
How could I test these APIs ?

I assume it means you need to download and install cURL, then run it from the command line.  It already gives you the syntax to input, which you've quoted here.

I assume it means you need to download and install cURL, then run it from the command line.  It already gives you the syntax to input, which you've quoted here.

Let me check it