1) Move sample_classroom.html out of lib folder so it's directly under WEB-INF

2) Add to homepage: 
<a href="sample_classroom.html"><b>To Classroom</b></a>

3) Add to sample_classroom:
<a href="register_4.jsp"><b>Home</b></a>

^^Change link address if the homepage changes.  It just needs to point back to the homepage.