How would i introduce my new guinea pigs?

[Emily]

Sunday im getting a new guinea pig.
I already have one, and i've had her for a little less than a year now.
even though i've had her for a while do you think would get along?

And i've read that if im getting a new guinea pig i should buy another cage and put one Guinea pig in one cage and the other guinea pig in the other cage.? Then put the cages close so they can smell each other.
if theres any information any one could give me that would be awesome[:

 

[Sarah Norton]

let em go free!