Carbon atoms can be linked together in such a way as to form rings. Let's examine the structure of (trans)-1,4-dimethylcyclohexane shown below. The cyclohexane part of the molecule is the hexagon part of the structure. All 6 carbons (C) are in the same plane in this drawing. This was merely done for the convenience of drawing this structure and the "real" structure of cyclohexane does not have all 6 carbons in the same plane. The 1,4-dimethyl part of the name indicates that on the 1st C there is a methyl group and on the 4th carbon there is another methyl group. The (trans) indicates that these two methyl groups point in opposite directions, one pointing out of the plane toward you (solid-wedge) and the other point back away (dashed-wedge) from the plane of the canvas.