Having a human is a big responsibility for a cat. You are entirely responsible for their health and well-being. So it's important to establish a proper exercise routine right off the bat.
Remember, if you aren't firm with them, humans can develop bad habits that will have a negative impact on their overall health throughout their lifetime. So the sooner you get them walking the right way, the better.
For a quick primer, watch this 7-step tutorial by Kodi the kitten. He's got his human trained and walking like a champ.