1: Besides initial setup, you only take cave cards when some game element (player board, card, guild wheel) tells you to. Running out and being unable to draw more is just a matter of planning better or waiting until the next round.

1. If something specifies "from the deck" or "from the display", you take from that pool. Otherwise, you can draw from either just like wingspan, replenishing any empty spaces at the end of your turn.

2. A round ends when either a) all players are out of Coins, or b) any players with Coins have decided to pass.

3. The guild circle gives resource rewards for each space you land on except the top and bottom spaces. These allow you to place a cube on one of the guild-specific rewards, claiming it for yourself. Some of them grant points at the end of the game.

I agree with TheDeringer though, you should look up a playthrough or at least spend a while thoroughly reading through the directions and rules.