Consider creating a Software Plan even if you customer does not require one.
It will help you with all the various task which need to be completed and in what order to get you to the final goal (completed software effort).
What are you input requirement (Documents, Table, Spec, SRS, meeting)?
Breakdown of individual software components:
(GUI, Power Supply Driver, Tests , Sequencer, Printout formats, Database)
Also indicate which task must be completed before proceeding to next.
All above should have approximate time, who will be doing the task, level of difficulty, comments.
Using a Spreadsheet application ,you can get approximate totals time, percent complete, and status.