Doesn't matter, you can do either...I did the software first....you can always add in the cable later....usually it's plug and play after installing bmw standard tools (EDIABAS needed for cable recognition)...sometimes you may need to use device manager to verify the COM port and may have to change it on the configuration file....it's an easy setup if you know how to use device manager on windows.
Like swamp said, you can use it without being connected to the vehicle...so just go browsing all the functions, etc....and you***8217;ll see it***8217;s really intuitive.