How can I build an FAQ Page with sections?
As an alternative to the FAQ Field module, you may want to use the Views Accordion module instead (for which an official release for D8 is already available), and its related Community documentation.

By "grouping fields", the group header can be used as accordion header. In your case, just use your "Sections" (like General, Printing, Binding) as those grouping fields. Obviously, you'd have to have a regular field (like a select list field) to actually indicate for each question in your FAQ what the actual Section for it should be.

With this approach, you have the full power of Views available to make your FAQ look like you'd want it to look.