The first step is to think about which protocol(s) you’ll be using, and then look up the Protocol Basics and Sequence of Operation for said protocol(s). This is because the protocols are fundamentally different, and you will need to know how to treat each one to get your desired result.
If you ever get confused about why the API works a certain way, or which standards document you should consult History and Concept for how we got here.
To get access to Kvaser’s J2534 DLL you need to install the CANlib drivers, making sure “J2534 driver” is selected to be installed (which is the default).