If there are not enough of a given resource in the supply to fulfill everyone's production, then no one receives any of that resource during that turn (unless it only affects 1 player). This means if multiple players should receive lumber but there's only 1 lumber card left, nobody gets lumber that turn.

No, you cannot play a development card on the turn you bought it. You must wait until a future turn to play any development card you purchase. However, you can play a development card at any time during your turn once this restriction is met.

Yes, if you have 2 or 3 settlements bordering the same hex when its number is rolled, you receive 1 resource card for each settlement. Cities produce 2 resource cards each when their adjacent hex is rolled.

No, players may only trade with the player whose turn it is. Other players cannot trade among themselves during someone else's turn.

If another player builds a settlement that breaks your longest road, and you no longer have the longest road of at least 5 segments, the Longest Road card goes to whoever now has the longest road. If no one has a road of at least 5 segments, the card goes back to the supply.

No, the Distance Rule prevents settlements from being placed at adjacent intersections. There must be at least 2 road segments between any two settlements, even if they belong to different players.

You get the Largest Army card when you are the first player to play 3 Knight cards. If another player later plays more Knight cards than you, they take the card from you.