I had the same curiosity (and the same "
THIS IS HAPPENING!!!" limitation to my attentiveness!

)... but just who
is this guy??
The character is Lor San Tekka, so I did a little 'nerding-around' on that, and found more questions than answers...
First (and least-likely IMO, due to numerous 'holes' and contradictions with
other storylines): Jakku was said to be an uninhibited desert plant, until the crash landing of the Star Destroyer(s), where the survivors established a settlement which became the village shown in The Force Awakens (this alone is where
many of the 'holes' and contradictions lie). Lor San Tekka was the commander of the Star Destroyer, and original leader of the settlement. He resented the Empire due to the lack of any rescue efforts at the time the Star Destroyer went-down (the Empire was “a little busy” at the time), so he became a rebel sympathizer. He had acquired that chunk of the Skywalker map and had it on-board the Star Destroyer while with the Empire (unknown to the Empire at the time) and after the lack of any rescue efforts, he had the strong desire to secretly get it into the hands of the Rebel Alliance... and the opportunity to do so finally happened many years later.
Again, I have little faith in that one... as I'm sure it can be ripped-to-shreds.
Second, with very-few details on this one... Lor San Tekka is actually Ezra Bridger in-hiding. Ezra was Padawan to Kanan Jarrus, survivor of Order 66.
Perhaps we will find-out more about this character in Rogue One?? We may hear a smidge about him in Episodes VIII and IX as dialogue to tie things together, but if this is an important character to the storyline, he would have to play a more-significant role in a movie with a prior timeline... like Rogue One. I found very-little details on Lor San Tekka in The Clone Wars series (but I didn’t look too hard, either!).
Cheers,
~TTF