I'll start by introducing myself. My name is Paul and I'm from the UK.
Over the past 6 years I've kept a multitude of exotics. Geckos, chameleons, snakes, frogs, darts etc.

I've had reasonable success with my terrariums in the past. Only ever bought stuff which is ready made though.
I've recently purchased an Exo Terra Large X-Tall (90x45x90) and I am hoping to create a living rainforest for darts etc.

Basically, I've done a lot of research online as to how to construct it. Everything from DIY backgrounds to various substrates, misting systems and plants.
In spite of all my research, I'm finding it difficult to get any kind of definitive answers to my questions.

I need to know your tips and advice please. Across the board from creating a suitable substrate, the best misting system to get and even the best places to obtain the necessary materials.
Whilst I am keen to get the best I can, I am somewhat constrained financially.

I also have questions regarding items such as expanding foam and other such things.

If anyone can help me with any answers etc it would be much appreciated.