A pushup is a simple exercise that uses a lot of different parts of your body. It’s also an exercise that requires no tools and can be done anywhere – beaches, ice covered ponds, airplanes, and boats.
Pushups are a great “building block” habit that keeps you coming back to your list of habits to mark off your progress.
Start with 4 sets of pushups (regular or modified, whichever you can do!) spread throughout the day.
In my habit tracking app I have “Pushups Set #1”, “Pushups Set #2”, and so on.
Here is a video I found particularly useful on proper form.