Most RSP units drill once a month. Your recruiter should help get you squared away with your drill dates for the next few months. Most try to do drill the same weekend each month (first full weekend or second full weekend, etc). It makes it easy to remember and helps families plan for the drills well in advance.
As far as the phases, just start by going in and learning as much as you can. Each state does the phases differently and depending on how fast you pick up material may depend on how long you spend in each phase.