Technique 1 - model the rows as normal. Then, make the next row above that, but move the edges in by a set distance (example 5m) as appears in the image above
Repeat the process of moving the edges in 5m each time until you have enough rows for your liking.
Done. This is the simpler technique.
TECHNIQUE 2: CURVES
As before, model each row as normal. I suggest making each row a component as it makes it much, much easier for the upcoming steps. Draw a line between the front of one row and the front of the row behind it and make note of the length of the line.
Open up Calculator, and multiply the number you just got, by the number of rows you want plus one. For example, if you want the curve to occupy 5 rows, as I do in this tutorial, enter 6. If you want 8 rows, enter 9.
Next, from the midpoint of the back row to the midpoint of the back of the row in front, draw a line.
From the midpoint of the back row, draw a line outwards along the pink axis (parallel to the last line you drew), type in whatever number you got from the calculator and hit enter.
Next, draw a curve from each end of the back row out to the edge of the line you just drew.
Now here is why you are better off using components. copy the back row up, to make another new row. Right click on the new component, click Make Unique and then double click the component. select the end of the row, and from the top of the rise, move the edge along the green axis (yours may be different) until you reach the curve. This will be apparent by a red square.
Repeat the process for the other side of the row, and then repeat the previous step - copy the component one row up. make unique, double click and move the edges along. You should see something like what is above.
Delete the lines, and explode the components if you wish, and you are done. The more rows you do, the better the curve looks, but too many and it looks unrealistic.
Now you know how to make a curve in a stand. The same principles work even if you aren't modelling the rows.