Hi
Looking at the back of the Apollo you are slightly limited. All I can advise on is the analog domain as this is what I use.
First I would watch this video regarding how to reamp with the Kemper.
This will help gauge what connections there are on the Kemper and what cables are required. If you want to just record the amp profile directly to the track you only need a single cable out the back of the Profiler to a mono input on your soundcard or two cables for stereo. These cables can be normal jack cables or balanced xlr cables as the Kemper provides connectivity for both.
If you want to reamp the video above will really help your understanding rather than me blabbing on about cables LOL. Also once you reamp its hard to go back. You can really tidy up a players performance and then play it back over 1000s of amps to get the settings perfect then record the final outcome. If you retain the dry track at any point to can reamp the track again if the song takes a different feel or reamp with a different amp to add depth.
One thing I love using it for is recording a riff in Cubase then moving the notes randomly in the editor to create an alternative pattern then reamp the track.
Hope that helps
Mike