Beginner "instead of cycling" workout?

Hi, I'm new :) First of all big thanks to Kelli & Daniel, your videos are probably the best fitness instructions I found on the web!

My doctor advised to go running or cycling to help get rid of/prevent migraines. But currently it's wayyyy to warm to exercise outside, so I'm looking for something low impact (neighbours below) I can do at home, at beginner level. My guess is anything cardio, but I'm totally new to this, so not sure haha. Any recommendations? :)