Postman application is a free tool which is a client for testing API endpoints. You can access the link below to download & install Postman application.
https://www.postman.com/downloads/
A Postman collection file is available through the following URL which you can import into the application to carry out testing.
{baseURL}/webservice/titusconnect/postman.php
Once Postman is downloaded and installed. Click Import and you can paste the postman collection file from the URL.
Once imported, it will create a new collection in the application.