The Past Indefinite tense is the second form of the verb. It is formed by adding the suffix -ed to the stem of the verb for regular verbs and is learnt by heart for irregular ones.
The negative and interrogative forms are formed by means of the auxiliary verb to do in the Past Indefinite. That is did.
The Past Indefinite is used to denote a customary repeated action in the past.
Last year I went to a swimming pool once a week.
В прошлом году я посещал бассейн раз в неделю.
Note: If the speaker wants to emphasize the regularity of an action in the past, he can use two special forms
used + to infinitive
would + bare infinitive
Sometimes used + to infinitive is used not to emphasize regularity but to inform about some change.
I used to think a wedding was a simple affair.
Я всегда считал, что свадьба - это что-то несложное.
The Past Indefinite is also used to denote a succession of actions in the past.
He stood up, lit a cigarette and came up to the window.
Он встал, зажег сигарету и подошел к окну.
The Past Indefinite can also denote a simple action in the past usually when the time of the action is indicated.
Yesterday I met my friend Boris.