The first thing you must do is to ensure that the new planks are exactly the same make and model as the existing ones.
Even though the new ones might look alike on the surface, various things like thickness and tongue and groove patterns wouldn't match up, leaving you with a floor that just doesn't match up.
Once you find your matching planks, you'd essentially remove any quarter round moulding and transition strips that locked the floor into place.
Depending on how much you will add and where it will be will determine the specific installation.
For easier reading about how to install laminate flooring, refer to the link below:http://www.homedepot.com/c/how_to_i...