First, hook up your output from the kemper to the amp input like you would normally. Instead of running a microphone, you will need to run a cable from the line out of the amp to the mic input on the Kemper. If your amp doesn't have a line out, you can use a Hot Plate or equivalent line out. You will need to have some sort of load on a tube amp - whether it's a hot plate or an actual speaker. Without this, your tube amp WILL blow up. As with any advice I give here, you try it at your own risk.
The only downside to profiles made like this is that they are specifically for use with a guitar cab and poweramp. You can assign a cabinet to it from another profile, but best results are from using them with a cab and poweramp.