Step One - Install the shower tray 

1. Place your tray where it's going to be installed and draw a pencil line onto the hardboard floor to mark the position.   Decide where the drainage pipes will be installed and cut out a small section of hardboard to make space for them.  Remember to check there's adequate room on the outside edge of the tray to have an access hatch to the pipes.   Underneath the edges of the hole you've made, nail pieces of batten and then cut out a piece of hardboard to fit the hole and place it on top of the batten.
   
   

2. Attach the waste outlet to the shower tray.  It's important here to double check there are washers or gaskets fitted on each side of the waste opening to make sure there's a watertight seal surrounding it. 
   
   

3. Using 4 parts building sand to 1 part cement, in your bucket mix up some mortar to a firm consistency.   Spread the mortar in sections on the floor where the tray is going to be fitted.
   
   

4. Move the tray into position, letting it bed down into the mortar.   Use a spirit level to check that it's level from all angles.  You might have to remove the tray and adjust the mortar beneath before you get it perfectly flat.
   
   

5. The final step is to connect up the trap to the waste outlet and join it to the waste outlet pipe.   Shower traps are fairly shallow, as a deep trap makes it harder to get enough space or height for a good run on the outlet pipe.

Here we use the example of a cubicle with a hinged door, as this is the most common type of shower door.  However, there are several other types of doors available.

1. The shower stall kit should come with specially designed channels that hold the sections of the enclosure to the wall.   You will need to place them in a perfectly vertical position on the corner edges of the tray before fixing them to the wall.  They will come with the relevant fittings included.
   
   

2. Decide where you want the door to be and then take the side of the cubicle that's to be fixed in place and slot it into the relevant wall channel.   Then place the opening section into the other wall channel and hold each piece in place so they join at the corner.  If you've got someone else on hand to help with this, it makes it a bit easier.
   
   

3. The next step is to fix the sections in position.  Use your drill to make pilot holes through the wall channels and into the frame, using self-tapping screws to keep them in place.   Make sure you use drill bits to make your pilot holes smaller than the screws.
   
   

4. Attach the door handle using your screwdriver.
   
   

5. The final and very important stage is to carefully fill in all the gaps around the internal edges and between all the joints with a silicone sealant, to ensure your shower stall is completely watertight and there's no chance of leaks.