It depends on your starting point, I reckon.
However, here's one idea.
Start by doing something that gets you out of breath & sweaty every day. Do it for half an hour a day to start with & you can build from there.
It could be that a walk achieves that for you, or if you're less unfit than that you may need to run up & down a staircase to get your heart rate up (be very careful not to fall!)
If you find a sport you enjoy, the motivation will come a lot more easily.
Try cycling & swimming.