Draw a line between N points to draw a polygon

I have copied a ASpawnVolume class (inherits from ACharacter) from 3rd Person Power-Up Game with C++ (v4.9) video tutorial. It’s a cube with 1600px of side. Inside this cube I’m going to draw the polygon in a 3D space.

I’m sorry, but I’m not very good with English and I’m not sure if I have answered your question.