Walking is a great low impact exercise and it is great to get outdoors and get some fresh air. Overtime you could increase your distance and remember to vary your route so you don't get bored.
We have a Walk It Out audio program if you would like to listen to next time or we have another walking program for the days that you cannot get outside that you may want to check out. Enjoy!
https://grokker.com/fitness/cardio/program/walk-it-out/5b5f7e2f82bb2874638aa0a8
https://grokker.com/fitness/cardio/program/walk-strong-low-impact-cardio-with-ellen-barrett/5887e4e30eeec67481fa03fa