What does Netfilter with the result of the modules called on hook?

Link of the tutorial (suggest me a better name): https://www.digitalocean.com/community/tutorials/a-deep-dive-into-iptables-and-netfilter-architecture

Thank you for the presentation of the nitty-gritty of iptables & netfilter. I would like to know how netfilter handle the result of the hooked modules.

As you explain, every module return an a decision to netfilter. As netfilter call all modules in turn, how it makes the final decision?

Thank.