chooding the values c,sigma

i am pusingsvm ,rbf kernal function,i that i have to choose values of c,sigma manaually,i referred

<http://www.mathworks.in/support/solutions/en/data/1-DO8141/index.html?product=BI&solution=1-DO8141>

in that 6 steps i cold not understand,what is grid search hoe to select values there ,can u help please