How-to mirrors in general driving
The general rule while driving use interior mirror.
Driver should be able to see everything needed through interior mirror.
Interior mirror gives a true picture.
Adjust the interior mirror when the car is stationary and you are seated in your normal driving position.
You should be able to frame the whole of the rear window in the interior mirror and be able to see the bottom part of rear window rather than upper part, cause the car behind is seen intiially in the bottom part of rear window.
Exterior mirrors are left mirror and right mirror.
Exterior mirrors made using curved glass, give a wider field of vision but judging the speed/position of traffic behind more difficult. Cars will appear smaller and further away than they actually are.
When turning left or right first check the interior mirror then left mirror if turing left, right mirror if turning right, then signal left if turning left and right if turning right.
When exit roundabout in any right exit (2nd, 3rd or more), before exiting from right lane to left lane, check interior mirror and left mirror, then signal left and change lane to the left, keep checking the left mirror while exiting the roundabout.