Any activities which distracts your mind from unwanted/ negative thoughts will be beneficial.
Try to have structure to your day.
Have a mix of activities which include physical activities like walking., yoga etc.There is no prescribed time duration for walks depends on how much time in a day you can spend on walks . May be 20 minutes walk every day and include some sensory activities that relaxes your mind like meditation, hobbies , things you enjoy doing .
Next Steps
Try to do mix of activities both physical and sensory activities as part of your day.