Бехруз, your question is very difficult to answer because Russian has absolute and relative tenses (There are five tenses in Russian - two past tenses, two future tenses and one present tense).
The present tense can express any tenses (present, past and future).
The past tenses can express past and future tenses.
The future tenses can express future, present and past tenses.
You have to learn the Russian grammar hard in order to understand and use them properly.