What is the best way to get started in this dive?
First step?  Find a local PADI or NAUI training center, or at least someone who is trained to teach SCUBA.  Do not go underwater with someone you don’t trust completely.  It is, after all, your life we are talking about.
You can read all about PADI and NAUI on their websites in the resource section.

NOTE: Do not buy your own equipment.  Not for a long time.  There is no point in buying your own expensive equipment when getting started when you can rent quality equipment for a fraction of the cost.