how to format x-axis to specific numbers? print screen shown

[bos1234]

I have the following figure below(see link). I have graphed QAM vs CAPACITY and would like to customise the x-axis to 4,16,32,64,128,256 as is on the table. I've placed the x-axis on the horizontal (category) axis label, however, excel has automatically formatted the x-axis. Is there anyway I could put the QAM numbers there instead?
http://s15.postimg.org/vrbc0hjnf/image.png

 

[Drrellik]

Bos1234, It is called format Axis and I am using excel 2013 so it may be a different but if you open you chart and click on the horizontal row at the bottom 0,l50,100,150... and then right click for format axis. I am not sure if you can put in the QAM numbers there but that is where I would start.