Types, uses & examples                               If-clause                                          Main clause
Type: 0 conditional  
Uses: facts and general truth                                   If/ when + present simple                                                   Present simple
Example: If you don't study, you fail.

Type:  1st conditional
Uses: likely to happen in the future                             If + present simple                                                      will and infinitive 
Example: If we have enough time, we will go out. 

Type: 2nd conditional 
Uses: unreal scenarios in the present/ future            If + past simple                                                        Would, might, could
Example:  If I had enough money, i would buy a new car. 

Type: 3rd conditional
Uses: unreal scenarios in the past                             If + past perfect               Would, might, could + have + Past participle 
Example: If Ali had studied, he would have passed the test.