New in here - and in wines

[Thomas Finn]

Me and my girlfriend have been drinking wines now for about two years, mostly reds, but we try to pick the right moments for reds and whites.

Anyhow... It wasn't until yesterday, that we got interested in the different types of wines. my questions are:

a) How many types of reds are there ? i.e Merlot

b) what's the differences between them?

Looking forward to read your comments...
Thank you