You could draw it by hand and have someone scan it for you...
But at a minimum, I'm sure the experts will want to know more about what you have planned before offering much advice.
Some basic questions will be:
How will you power the system and element(s) on and off?
How many elements will you use, and at what wattage?
If using more than one element, how will you switch between elements?
Are you using PIDs?
I'm not an expert either, but here's my understanding: Most are using contactors (relays) to carry the load for switching, so that a high amp switch is not required. The extra switching is really a safety factor (i.e to switch the element or entire panel off, so that it is really off). If using a 240v element, turning off one leg, only stops the heating function - but there is still power going to the element.
Hope this helps,