>>>1.What exactly is the deal with "hides"??
Hiding spots. They like hiding. Makes em feel safe. These can be anything from store bought ceramic "caves", fake or real concealing plants, or even el-cheapo tissue boxes or shoe boxes, I even heard of people cutting a hole in a check box.
>>>2.How many should I start out with?
Every tank should have at least 2 hides. Put one near the warmer side, put one on cooler side.
>>>3.What is an ideal setup for beginners?
Ideal? Define ideal.
Ideal for money? Be creative for tank "furniture"...cardboard boxes instead of store bought "caves", etc. They won't notice, nor will they really care if you use a box.
Ideal for ease of care? Paper towels and newspaper substrate cant be beat. Cheap. Easy to clean.
Ideal for looks? Lots of fake caves, real rocks, plants, sand substrate, etc. This tends to be more expensive.
Ideal for the animal? Ideal for a leopard has several hides, one of which is a moist hide (has some slightly moist paper towels or vermiculite), a heat lamp, a water bowl, and a vitamin/mineral bowl.
Add a small branch or something similar. I like to angle these close to the lamp so if they want lots of heat, they can climb closer.
Some fake plants and maybe a few carefully placed rocks (so they dont fall over or tip) for extra hides are good too.
I've come to find that "ideal" setups for me are the ones that are very simple, and easy to clean/maintain.
>>>5. What is a good substrate, other than newspaper and stuff?
Haven't owned a leopard gecko yet (my fiancee is buying some soon). Everything I read says papertowels or newspaper for geckos under 6 months of age. Sand is fine for adults. Me, I'd use the calcium sand to be extra safe.