Oh forget it. I don't have the patience or time to learn that program. The help doesn't help. This is what I am suggesting:

Make your enclosure at least 48 X 12 X 12. No taller than 16 inches from bottom to top. It can be longer or wider but keep it 12-16 inches from the screen top. No more. Keep your water area no more than 8 X 12. Do not use glass on the top. Use all screen. Screen must be strong, non-corrosive, heat resistant and tightly secured. Do not use wood for the interior walls. Use glass or plexiglass. You will need to create a raised lip or edge so you can put 2 inches of substrate in there without it falling into the water. Sliding glass doors must also be raised off of the floor so substrate will not get out or into the slide path of the glass.

Do that much, and your substrate will stay dry and humidity will be acceptable.

Simply heating the end that does not have water will cause air to rise. That will make The rest of the screen top bring fresh air in.

keep the water area below 10% of the total area and keep it dry. A water feature is fine but snakes live on land. The air must be fairly dry and so must the substrate.