Russian Verbs - Past Tense
Today, I thought I would quickly divert to past tense before diving into "Быть". Past tense behaves differently instead of different forms per pronoun. There are only four forms for masculine, feminine, neuter and plural forms. For instance, our old acquaintance "to work" i.e. Работать.
plural (мы/вы/они́) работали masculine (я/ты/он) работал feminine (я/ты/она́) работала neuter (оно́) работало
There are some differences based on the stem and some historic exceptions but the main categories are explained well in these two resources. First of, there is Past Tense of the Verb - Learn Russian Grammar that includes some exercises and Ru Land Youtube channel video: