The Great Icosahedron is one of the more complex polyhedra on this site. It is also one of the most difficult to assemble.
To create the Great Icosahedron, you will need 12 nets (page 1 of the worksheet). Each net will create 1 point on the Great Icosahedron. One page of the worksheet has 4 nets, so you will need to print 3 copies for each Great Icosahedron. Print the nets on card stock. The paper should be stiff, but not too thick.
You will also need to print 1 copy of the page of triangles (page 2 of the worksheet). The triangles are used to provide internal structure for the Great Icosahedron.
A greater selection of polyhedron patterns can be made from Stella: The Polyhedron Navigator.