I am still not persuaded with the explanations of the twin paradox which I can find over the internet, so I am posing an extended version:
Consider triplets - one travelling to the west, one to the east and one staying. Given the fact, that the two of the triplets travel at different directions, the regular explanation will not be suitable. Can sb. elaborate?
A spacetime diagram on rotated graph paper allows ticks to be read off.
Essentially, follow the bouncing light-signals (arranged so that the principle of relativity is satisfied), which bounce off parallel mirror worldlines [not shown].
All light-clock diamonds (which visualize the ticks of a wristwatch) have the same area.
Here is one for the problem you pose.
The light rays broadcast by the initially-forward-traveler are shown, which can be used to compare what the other observers see with their eyes to compare the remote clock-face with the local clock-face (associated with the Doppler effect).
The most time elapses on the inertial path from separation to reunion.
This diagram is taken from my earlier answer https://physics.stackexchange.com/a/402711/148184 from What if two twins flew off in opposite directions and were reunited in a perfectly symmetric way, would they have aged same?
A more elaborate explanation is at another answer https://physics.stackexchange.com/a/434193/148184 from Question about Special Relativity similar to twin clock experiment
UPDATE:
For something with asymmetric motions, go to https://physics.stackexchange.com/a/508935/148184 from Equivalence of two definitions of proper time in special relativity
