While keeping the rectangular foam block upright, rotate the screwdriver up through the base of the block to make small vertical tunnel up in the center of the foam. Make sure that you do not push in the screwdriver all the way through. Leave the upper portion of the tunnel capped off by the foam.
Make use of the utility knife to cut a little portion of the bottom of the foam block to give it a look of a shape which is more or less similar to a water pump. A canvas shape will be ideal as it will hide the pump with in the bottom of the foam block.
Get hold of the screwdriver again and use it to make a hole. Make a horizontal hole near the top of the block so that it coincides with the vertical tunnel. The hole that you make will pump water.
Take a tube and inset it through the holes that you made with the help of the screwdriver. Make sure you do not go overboard with the tubing, as the water that it will pump will spray all over the vivarium and won’t serve the purpose.
Secure the water pump and connect its output with the open end of the tubing. The tubing should be such that it fits with the output of the tubing.
Connect the water pump to a source that provides it with electricity to run it. Find a nearby socket and insert the plug to get the water flowing. If it is possible for you, take the reptile out of the vivarium as they will get highly annoyed with you disturbing their territory. Cold blooded animals are otherwise unpredictable, and have been reported in the past to strike their owners at the most unexpected of times.