i would like to replace water pump?

Yep, that is a fun car. You will need to replace the timing belt at the same time so I would do the tensioner for that as well. Here is an exploded view of the job so you can replace the water pump, I also included the timing belt marks so you can complete the job. Check out the images (below). Please upload pictures or videos in your response of any problems so we can see what to help you with.