Everyone does all of them. It's just that there's one in each category that a person prefers using.
The Judging/Perceiving category tells which function is extroverted. If the person prefers Judging, then the Thinking/Feeling is extroverted, and if the person prefers Perceiving, then Sensing/iNtuition is extroverted.
In the case of an ESTP, the person prefers first Extraverted Sensing, and then Introverted Thinking.
In the case of an ISTP, the person prefers first Introverted Thinking, and then Extraverted Sensing.
I'm sure that only served to confuse you more, but that is the answer.
Hopefully it did help you to start understanding it better.