What type of employment, literary and financial ambitions do you have?
What genre of book have you written?
I wouldn't recommend publishing on amazon if you want to make a living from writing.
Quite a few friends have done so, the earnings are generally miniscule (usually less than £200).
The best things to do are get some advice/feedback/mentoring on your completed script and writing skills from an experienced professional working in the publishing industry.
Then focus on widening your writing skillset & networking contacts and building your profile in the writing & publishing worlds.
This is what I have spent many years doing.
Good luck!