We all start out somewhere. My first enclosure or my second were not all that great lol. Ok you want to measure down from the screen 9 inches... Then you want to place in horizontal branches on your sides front to back verticals. Do this on both sides. This gives you your basking level. From those horizontal you will run your basking level branches. See red horizontal bracing branches... All yellow are your tie ins and basking. You can add more branches down through the middle as well. This will allow him to use more of the space.
Now all the plants in the bottom are going to struggle. Not enough light. Do yourself a favor and pull those out that are sittin on the bottom. Get a nice big centerpiece plant to stick in instead. Home depot or lowes indoor garden section. Draceana are good as well for adding coverage and height. See if you can find a nice ficus or umbrella.
How many nozzles are you running? Looks like 4 which will be overkill in that size enclosure. You can make those into single heads by pushing and pulling the pieces apart. This is why your pothos on the top is starting to yellow. Too much water. It will also push your humidity far too high during the daytime.
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