Can you please check this DB Model and provide insights on how we can index the tables

What and how to index depends on how the application uses the tables.

You really  cannot say what indexes are necessary based on a model.

Tuning is more of an art than a science.  Pick your worst performing queries and tune them individually.  Keep on until you are satisfied but be careful to not over index...  Too many indexes can also hurt performance.

I'm rusty on the notation.  Within a section, do you have one, or multiple hyperlink?  Can a hyperlink populate multiple sections?

I'm speculating (again, rusty), you may be unnecessarily replicating the parent PK down to each child.