You might get more out of this if you post your specific situation with details about the relationship, people involved, ages, past experience, etc. You may start a threat under "Poly Relationship Corner" explaining what's going on.
There's no one answer to what a "baby step" is. It would be different for each person and situation.
Is poly something you really want because it feels right to you, or is it something your partner wants and you are trying to accommodate yourself to the situation? Your approach and our advice to you might be a little different in each case.
Single, straight, female, solo, non-monogamous.