I’m still not getting what you are asking.
Open book is what it sounds like. They mail you a test and you complete using any reference publication you want, and mail it back. It’s two modules, rules, and another for everything else except navigation problems.
Assuming you don’t have the one year of sea time in the last five, and that this is the first time you are renewing since 2017, you would need the open book at hom,e test for your license, and for STCW:
Basic Safety Training Refresher course(s);
PAdvanced Firefighting refresher;
Proficiency in Survival Craft Refredsher; and
Leadership and Teamworking Skills.
The Leadership requirement is one time only, and is either assessments or a course for OICNW, If you aren’t sailing now, the course is probably your only option. If you have plans to upgrade to Master or Chief Mate (including Master 1600) consider the longer Leadership and Managerial Skills course. It will do what you need now, and you won’t need another course when you upgrade to Chief Mate/Master.