Just by clicking on  the add button (which is plus sign has reverse yellow triangle at base). By clicking on it, one can add the desired layer after browsing the files in computer.

Here we can change the order of layer, color of layer, outline  and width of the layer . It will be set.

I browsed this very useful data of cancer mortality from

http://ratecalc.cancer.gov/ratecalc/

This website I found very useful for cancer mortality. I can have data in excel forms. I can use it for various softwares , and even with GIS.