What were the Japanese actions that led to the attack on Pearl Harbor?
In general, the Japanese actions that led to the attack on Pearl Harbor (other than the actual planning and carrying out of the attack) were actions that showed that Japan was trying to take an empire for itself in Asia and the Pacific.
These actions started after WWI. Japan took islands (Micronesia) that had belonged to Germany and essentially made them part of its empire. Japan was not supposed to be doing this, and its actions worried the US to some degree. Later, Japan started to invade the Chinese mainland. Japan first occupied Manchuria, ignoring the League of Nations when that body tried to tell it to leave Manchuria. Then Japan invaded China. Both of these actions worried the US still more because the US felt that a large and powerful Japan would be a danger to US interests.
The Japanese action that led fairly directly to the Pearl Harbor attack came in July of 1941. In that month, Japan occupied French Indochina, mostly what is now Vietnam. The US felt that this was the last straw and that Japanese expansionism needed to be halted. It cut off sales of oil and scrap iron to Japan. This led Japan to attack Pearl Harbor.