I wouldn’t use things from outside because of mites and other parisites being pasted to the Iggy
You can use things from outside as long as you boil them before putting them in the tank to kill mites etc.
Here’s a good pic of a homemade hammock, maybe you can get some ideas from it:
pillow case and stuffing
Hammock would work nicely local petstore.
The thicker the enclosure simple hooks will either have to the sides of almost any material the thicker the thicker the better id.