This lesson says «present tense is used to talk about the past event», which is fine, in English too it happens.

However, there is another lesson in C1, «simple future or conditional tenses are also used» to talk about the past event.

Can someone please explain when to use the present tense, and when to use simple future/conditional to talk about the past event? Or, in the same situation, present tense and future/conditional tense is inter-changeable??