Hi,
I'm confused. Is it possible to participate in community events with the GOG version of NMS? If so how?

Thanks

You need to install the game using GOG Galaxy, or just install galaxy and point to your existing game install.

Yes.

There usually are triggers to get each mission started. Not sure how things change if a player is just joining.

Look in the Log to see if the mission is listed and select if it is listed.
You might have to find a Space Anomaly and interact with Polo to get the missions started since your question indicates that you never participated in one before. For an anomaly to appear you must have completed at least three warps and a few hours of game time.
With the mission selected scan in space. This can trigger a message that will start things.


Good Luck