Having trouble extruding a cube. Basic question!

Hi I’m just starting out to learn unreal and I’m having some basic technical problems. I’m presently doing the tutorial which asks me to extrude a cube however in this tutorial the cube looks like a simple square.

However when I load it up. It looks like a Yellow lattice and I cannot get it to change.

I’ve uploaded some screenshots. I’m not sure what I’m doing wrong! help!