Скачать или смотреть Pluto and Charon are a fine example of how bodies orbit the center of mass (barycenter)

Here the barycenter is completely outside of Pluto all the time, so you could say this is a (dwarf-)double planet system. Charon is 12% the mass of Pluto, and they're BOTH tidally locked!
About tidal lock: here each body sees the same face of the other body all the time. That means the rotation periods AND orbit periods (around Barycenter) of BOTH bodies are the same; in this case 6.39 days. How convenient that we only have to remember 1 number for 4 parameters.
It's worth noting that tidal locking doesn't always mean two bodies face eachother, but it's usually the case. Mercury for example is in tidal lock with the Sun, but it rotates on its axis three times for every two orbits it makes around the Sun.

Imagery from: NASA / USGS / Solar System Scope processing https://www.solarsystemscope.com/text... under CC BY 4.0
NASA ephemeris data: https://ssd.jpl.nasa.gov/horizons.cgi...