the task is a relatively easy one to someone with basic diy skills, but to a novice, even changing a plug can be quite a task, and this particular job is very similar to a plug change.....the new inline rocker switch will indicate the position of each wire and ensuring these wires are fitted tight is essential as said in other answers.....to be honest if you are this much of a novice I would suggest either get an electrician or replace the lamps as mistakes ( even the simplest ones ) can be life threatening......always stay safe!!!!