How are projects managed – task break down, providing estimates, cost break down (?), and setting deadlines.

I’m trying to understand better how projects are carried out at organizations/individual levels. Specifically how a project (ideally software) tasks are estimated and how project timelines are set and delivered. Can anyone help me with this by filling out this survey?

https://forms.gle/XBpFnFZMqvpF5MKU7