Box-and-whisker plots are a brand new concept for my 6th-graders, and when students are first introduced to them, they seem a little scary. However, with some structured directions, students catch on very quickly.
I break down the box-and-whisker plot into 5 steps, in order to plot the 5 points needed to create the box and whiskers:
1) Order the data set from least to greatest.
2) Identify the smallest and largest values; place those points on the number line (above the number line).
3) Identify the median and place that point on the number line.
Students need to remember that if there is an even number of numbers in the data set, the median will be the mean of the two middle numbers - even though they've found median in the past, many students tend to need this reminder.