If you want to start, easy exercises for starters is the key. You can not just go from your home couch to regular exercise program in a matter of days. Starting an exercise program should be done slowly, and even with a doctor’s supervision if you have medical issues. There are many exercises that are perfect for beginners, and these will allow you to build up muscle and strength, while improving your endurance and overall health. Before starting any exercise program it is always a good idea to check with your doctor to ensure that there are no medical conditions that need to be considered. Always warm up and stretch out before beginning a workout, so that your muscles and body are loose and limber. This step will help prevent any injuries like strains and tears.
This is great you have started to walk which you enjoy, as walking is one of the most important exercises. Later on you'll feel the need to add more exercises. Please do it gradually. Take your time. Make your workouts interesting and enjoyable. CU around and good luck!