Overview of how to build an “Actions/Activity” feature like the one in trello, where all actions are displayed in a last in time descending order

If I wanted to build a feature into my app as the one in trello where the latest actions of the team are displayed in a list order in descending (time). How would you design such a system to track actions?

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What is differences between primary actions and secondary actions for checkbox?

material design

While reading material design, i found that i didn’t know the difference between primary and secondary actions. I think it’s too basic, I can’t find any information about it. What is the difference between them especially in check boxes? and can i get some example about it..?

about image / 1 is about secondary actions and 2 is about primary actions