So ethane looks something like this, where these two black intersections are our carbons. So carbon one and carbon two given by these two carbons on the board. Now, these rest spheres are our H atoms. So we have six altogether. Now, these black solid wedges are our Sigma bonds, the Covalent bonds coming out of the board given by these two bonds here. These dashed wedges are given by these two bonds, sigma bonds in the back.