The Truman Doctrine arose from a speech delivered by President Truman before a joint session of Congress on March 12, 1947.
Positive First. When installing a mower battery, always connect the positive cable first. The positive cable is red. It attaches to the battery terminal post marked with a plus sign, the letter P or the word POS. Attach the negative cable last. The negative cable is black.
First connect the positive (+, usually red) jumper cable to the positive car battery cable, & then the other end of that jumper cable to the positive external battery terminal. Then do the same with the negative (-, usually black) car battery cable & jumper cable. The last thing you connect should be the far end of the negative jumper cable to the negative terminal of the external battery.