Hi Rhonda
Welcome and Happy New Year
It should just plug into an extension cord to work.
If you are really quite when you plug it in you should hear it start to heat the water like an electric kettle.
Or if you have a volt meter you can check to see if the heater is good by using the continuity setting and put a probe on each flat prong on the heater cord if the heater is good the tester should make the same sound as when you touch the prongs together.
Thomas
90 Chev 3500 c/c 4x4,6.2na,400 auto,4:10 gears.DSG Timing gears,main girdle, isspro tach, pyro,boost,oil and trany temp.Dual Tstats, High volume peninsular pump,on shelf, Custom turbo and intercooler 85%complete. Change of plans for the dually, it's going to get a Cummins. Both trucks are Blue 90 4x4 crews