Sometimes we call them 'if clauses'. They describe the result of something that might happen (in the present or future) or might have happened but didn't (in the past) . They are made using different English verb tenses.
Actually there are 5 types of Conditionals in English Grammar:
1) Zero conditional
(if + present simple, ... present simple) If you heat water to 100 degrees, it boils.
2) First conditional
(if + present simple, ... will + infinitive) If it rains tomorrow, we'll go to the cinema.
3) Second conditional
(if + past simple, ... would + infinitive) If I had a lot of money, I would travel around the world.
4) Third conditional
(if + past perfect, ... would + have + past participle) If I had gone to bed early, I would have caught the train.
5) Mixed conditional
(if+ any grammatical time from previous types, ... any grammatical time from previous types)
The most important thing that we should remember when we learn conditionals: NEVER USE WILL+INFINTIVE (FUTURE SIMPLE) after IF.
This week we will practice Second conditional, that is why remember the construction:)