Measure the Space

• Use a tape measure to take all measurements for length, width and height of your shower. Also measure the distance needed above the shower insert for the shower head. If you want to use existing plumbing outlets, measure to make sure they are compatible with any shower insert you select. Make sure you have ample room above the shower inserts for ceiling clearance. This can sometimes be a problem in older homes.
  
  

Choose the Inserts

• Pick either a plastic, acrylic or fiberglass insert. Plastic and acrylic cost less and are easy to maintain. Fiberglass is a heavier material that wears well. Each of these materials is available in a variety of colors to match your decor.
  
  Find the shower insert material that offers the accessories you desire. Built-in soap racks, shampoo holders and washcloth holders are just a few of the options available for a shower installation.
  
  

Install the Inserts

• Use a pencil to mark on the back of one of the inserts where the plumbing fixtures go. Drill the holes. The fixtures should extend beyond the insert when it's set into place.
  
  Prefit the shower inserts. Make sure everything is going to fit exactly as it should. If not, you may have to shave a bit off the flat end of the panel (not the grooved end) in order to get a tight fit.
  
  Apply silicone caulk to the base of the left panel. Use a quality construction adhesive on the back of the left panel and on the wall behind it.
  
  Set the left panel into place. Gently pull it away from the wall to allow the adhesive to become tacky. Then firmly push the panel into place. Repeat this process for the remaining panels. Make sure the panels fit properly into their respective grooves at the corners.
  
  Add a line of silicone caulking along all seams to finish the panel portion of the shower installation. Finish the edges with silicone caulking and trim. Allow all of the caulking to cure according to package directions before using the shower.