Conditional statements concern a circumstance (or condition) that influences the results or probable results of an action. There are two basic types, real (factual) and specious (only possible).
The tense of the verb in the second clause depends on the tense of the verb in the first clause.
1.a. If ice melts, it is warmer than 32°F.
1.b. If ice melts, it will be warmer than 32°F.
2.a. If he studies, he will be successful.
2.b. If he studied, he would be successful.
2.c. If he had studied, he would have been successful.
1a. Scientific fact conditional. That fact that the ice is melting will always mean that it is warmer than 32°F. Present tense in both clauses.
1b. We can also use the present and future tenses for the scientific fact conditional.
2.a A future action depending on a present action. Present tense in the “if” clause and will/can/may + dictionary form in the second clause.
2.b A present action depending on an action in the past. Past tense in the “if” clause and would/could/might + dictionary form in the second clause.
2.c A past action depending on an action further in the past. Past perfect tense in the “if” clause and would/could/might + have + past participle in the second clause.