That’s done with the Text tool found in the Tools menu. It will give you the coordinates of points in the model if you click on them.
Push/Pull works perpendicular to the faces. As Simon suggests, you could outline the end of each piece on a larger face and pull it out. Make sure that larger face is a component or group first. Then Make sure you make a component of the shelf part before you move on to draw the next one.
If I were modeling this shelf from scratch I would not worry about the bevels where the parts meet until after I have the shelves positioned. Like this:
You can adjust the angles as needed until you’re happy with it and then go back and add in the bevels. The bisector is easily found by connecting the top and bottom points.
I would start with one component, copy and rotate it and use Make Unique as needed. It’s easy enough to make copies with Move (M) and Rotate (Q) them to the desired angle. Change the length with Push/Pull (P). Once you’ve drawn the first piece those three tools will be all you need until you get to making the bevels.
How will you join the parts together? Biscuits? Dowels? Domino?