Where do I start from?

Hello everyone!

I am new in the API universe, middle-aged with very little training on XML....but very anxious to dive into this world.

I used Ready API v.2.0.2 today for the first time, I can successfully send and receive data to certain applications (WSDA) but what then? How do I use the responses I am getting from outside systems? In other words, what tools are there for me that I can use to a)Trigger the transaction from a normal web page to the third party application outside of API v.2.0.2 and b) to display this information to my users?

May sound elementary, but this is what I am puzzled about; any help will be much appreciated. Thank you!