When dropping a ball a free drop is one club length and a penalty drop is two club lengths.
You must drop the ball at the nearest point of relief not nearer to the hole.
If your ball is in a bush you get a penalty drop of two club lengths from where your ball lies, if that still puts you into the bush then you take one of the other two options available to you. You can go back in line with your ball and the flag as far as you like (One penalty stroke). Or you can go back and play from where you played your last shot. (One penalty stroke).
If your ball lands on a bridge over a hazard you do not get a free drop unless it is a local rule of that course,you must play the ball as it lies or take a penalty drop.
If you cannot find your ball, you cannot go back and play a provisional ball whilst your playing partners carry on looking for your original ball. You cannot play a provisional ball once you have left the last place you played your shot. If you do go back and play a second ball that is the ball in play even if you or your playing partners find your original ball, once you play that second ball that is the ball you complete the hole with. With a penalty of one stroke.
Tree basins are not a free drop, unless it is on the scorecard under local rules.