when everything is worked out in the book but there are a few chapters left and when nothing is right in the book and there are only 20 pages left.

I've redrafted my plot in the form of a short story several times till I am now happy with it and stitched every ends together.

I have an idea of the characters' goals, conflicts and resolution.

I don't know if I'm ready to write the novel itself. How do I know? What else do I need to do before I write it?

Is writing down the scenes with more details of the settings and conflicts before writing the actual novel a good idea? Or should I not do that?

Kantia Island, a remote island in the Caribbean Sea. The natives are mixed-race of Creole, Carib, Spanish, German and English. The island is pristine with its beaches, tropical rainforest, high hilltops, deep ravines and green vines.

The islanders, however, are a mess. For centuries, Kantia was, and is, anti-medicine, anti-vacciniation and anti-psychiatry. They have been plagued for so long that their disorders have become ambiguous. They have convulsions, erotomiania, hypersexuality, strong mood swings, manic, playing with pyromania, melancholic, spasmodic cackling, tremors, and bleeding from their pores. They even have developed to practicing cannibalism when their farming/fishing produce has failed.

The madder ones roam about the island in a bestial manner and making snarling sounds, while the less madder ones organize and work in the community.

got a context?

presumably you arent referring to a bound volume of printed material

to charge - The police booked the suspect.

to maintain a gambling record - Charlie kept a book for the Saturday horse racing.

make a reservation - I will book a table for dinner tonight.

and others ......