First Conditional

We use first conditional to talk about possible future events which depend on other future events.

if [Present Simple], will + [infinitive]

 If I go to the cinema, I will see an interesting movie.

Second Conditional

We use second conditional to talk about imagined, unlikely or impossible events in the future.

if [Past Simple], would + [infinitive]

 If I had tickets, I would go to the cinema.

This conditional can also be used to talk about impossible present situations.

 If I had tickets, I wouldn't stay at home.