Short for Metabolic Conditioning — essentially workouts that will improve how your body delivers and utilizes the fuel to target muscle group.

More often than not, the first thing that comes into mind is cardio workouts. However studies shows that weight lifting can also achieve the same objective, depending on intensity.
HIIT (High Intensity Interval Training) is considered one of the most widely regarded metcon. This is especially good news to those who preferr something a tad more variety and more intensity (like yours truly).

Another benefit of metcon is that you can design your own routines – with bodyweight. By learning variations of pull-ups (aided or not), push-ups (aided or not) and different variations of lower body movements, one can achieve a complete body workout in as short as 20 minutes.

© Masta4650 | Dreamstime.com

So what can you do to start?
You may start with pushups or squats, like 5 sets of 30 squats, 1 minute rest in between, everyday.
As you progress, add more reps and reduce the resting time.
Then mix things up, for example a set of 5 pullups, 10 pushups or squats. The objective is to condition your body to recover and get ready for next set. You may design the routines as you deem fit! (Of course, more growth and improvement can be achieved with more reps or harder moves).

One last thing: You might want to remember to breathe.