Present Moment Introduction

This is a working theory on the present moment that came to me a few days ago. This theory is still developing and in no way is completely worked out.

I have thought often on the special relativity thought experiment of the twin paradox. There is a main theme that I can not quite understand. How does the twin who went into space return to the exact present moment to find the twin who stayed on earth?

I understand completely how the space traveling twin finds the year bound twin in space. Coordinates are used to locate the twin on earth. But how do they find each other in time. There is only answer that comes to me. There is only one present moment to return to.

If there is only one present moment then how is the space traveling twin younger than the earth bound twin? How does this eternal present moment function in this context?