A Hairnewb's Questions

I decided to get something done to my hair, and went on a big research trip on the internet.

I think I'm about done, but have a couple of questions before I jump into it.

I have been very anti-fashion, and even what seems obvious to you is new to me, so please, don't hold any tips back.

1. What are the general differences between male and female haircare? Any tips found on a website possibly catered to females I should disregard?
1. 1. For example, it was recommended for long haired people to sleep with scrunches. Does this concern men too? And does medium hair classify as long or short hair, when only those two terms are used?

2.What are the following, and how do they relate to the rest of the haircare routines? (Are their effects nullified by other treatments?)
- Once-a-week treatment
- Hot Oil Treatment

3. Is trimming versus cutting simply referring to the differences of hair cut off? What are these?

4. Hairbrushes. I got them all summarized, but didn't actually find out which to use when and in which order... And when exactly do you use...

5. Combs?