Want to learn SAP PI 7.4 Single stack

Hi Experts,

I am a beginner in SAP PI and started by journey with SAP PI 7.0. Now, we are upgrading it to SAP PI 7.4 single stack.

I want to learn it as much as possible before the migration but when I search for the topics in SCN, I am getting confused with the different topics and its naming conventions explained. (For Eg PI and PO). So, will it possible for you experts to provide me the links which can actually help me to get the full depth knowledge on PI 7.4 (Single stack). Am just hoping to be a productive member of this SAP family:)

Regards,

Adarsh