Problem 6.1

Cut out the block and color some of the layer, it will help
  1. Crestal trough trace - Intersection of the troughs and the surface
  2. Axial trace - Intersection of the axial surface and the surface
These traces may look similar but they are slightly different

Make sure you describe the folds as suggested in the problem. I am ok with a bulleted list

Problem 6.4

Look at Figures 6.13 and Figure 6.14 for an example of a vertical axial surface.

For any cylindrical fold, the dip and direction of the bedding at the crestal or trough trace defines the fold axis.

For this problem, you need to define the crestal or trouch trace. Along this trace you can use the dip of the bedding to define the orientation of the fold axis.