Please click on these links to see a simplified explanation.
Zero Conditional - If I don't breathe, I die.
First Conditional - If I eat too much, I will get fat.
Second Conditional - If I won the lottery, I would buy an island.
Third Conditional - If I had studied more, I would have passed the exam.
3/2 Conditional - If I had woken up earlier, I would be at work now.
2/3 Conditional - If I were smarter, I would have passed the exam.
1/3 Conditional - If you are so smart, you would have gotten 100% on the exam