Here is a feeder cup you can mount to the wall using zip ties or other coated wires.
Get a regular water bottle or a small milk carton (not the gallon).
Cut a square hole in the front.
Should look like this (stole the image from another thread).
Then, get a stapler and some felt or carpet scraps (mesh works too). Anything kind of fuzzy for some bugs to grab onto. As long as the bug has legs you can put them on it and they will hang on the felt.
Staple the felt/carpet to the back right across from the hole you cut.
Now take some wire and mount it to the side. Make sure the hole you cut is not going to harm the chameleon.
Here is a good video
examples- you don't really need instructions to make a feeder cup. just take a good look at some example pictures and copy some of the ideas.
bird cups. you can easily buy one of these and mount it to the screen if the screen mesh is wide enough to hang the cup from
screameleons company did this one. its simply a cup with a wire harness around it that you can hang to stuff.
this one is from a quart of milk carton I think
see how you can staple mesh to the back so bugs can climb?
this is how you could possibly fasten the cup to the screen
Or you could use zip ties and hole punch the cup in 2 spots. now you can fasten it anywhere you want with zip ties or wires