How to create and manage tasks in odoo 13 project?

Hi, thank you for the explanation video. Can you tell me what to do with a task once you finish it? I can change the task to the fase "Done", but it will still tell me that I haven't made my deadline. Is there a way to complete a task without deleting or archiving it? Thank you!

Hi. Thank you for the video.
If we have 2 separate employees for Initial Stage and Recruitement Stage, and if task in Initial is completed, how can we assign it to automatically make the task go from Initial to Recruitement? (i.e. from employee 1 to employee 2)
Can you please help me with this. Again thank you.