Navigation elements (buttons, links, instructions) help visitors to your
site find their way around. As with other design considerations, consistency
is the prime factor in navigation design. Put your buttons, links, etc in
the same place on all the pages of your web site or, if you must move them,
put them in predictable places.
The overall design of a navigation scheme should reflect the decisions that
were made about the organization of the web site. Build in navigational elements
that will naturally lead visitors to navigate the site in the way that you
intended. It might be important that your students progress through your curriculum
web in a predetermined order; it might be better to let the learner choose
where to go in completing a learning activity.