I don't now how to fix my leaking triton bermuda shower?

Hi my Triton Bermuda shower is leaking,its coming from a see through tube out the bottom of the shower plastic cover tat covers all the working parts of the shower.I have had a look on the internet to find a picture of the working parts and it was number 13,I'm sorry that I can't name it but I would like any help given Ive managed to take the plastic case off put I don't have a clue.