Correspondence Chess Question

Maybe I’m just dense, but what does this mean?

" Send your first move as White to your opponents as indicated below.

Player #1 receives first move from 2,3,4; Player #2 sends to 1, receives from 3 and 4; Player #3 sends to 1 and 2, receives from 4; Player #4 sends to 1,2,3."

When is Player 1 supposed to send his first moves as white? Are all six games not played concurrently,but 3 at a time?

Player 1 waits until he receives the White move from each of the other players, then with Black can reply to that move and also send his White move to that player on the same card. You play all 6 games at the same time.

I see, thanks!

If my opponent sends “Nd2” and two knights can go to d2, can I choose which one to put there?

No. The move is considered ambiguous and must be clarified. Check the rules you got with your assignment. There should also be a time penalty.