I suggest trying to break up all the tasks that make up your project into as many discrete “single serving” tasks as possible.
The reason for doing this is simple.
We want to be able to measure & communicate progress for you and your client. Small tasks can be worked on or paused as needed.
This allows you to complete tasks in the order that makes sense for you, while still being able to see overall progress being made.
This is important data for you & for your client!
If your only task is “To finish the project!” depending on what the project is, that “task” could take a LONG time!
The goal is to not just to record how much time has been used, but to discover where time is being utilized.