I'm So Clueless

I have no clue when to start anything! Do I sign up for birthing classes now? Later? When? Do we start thinking of names now? When we find out the sexes? Do we pick the nursery when we find the sexes? Do we tell family and friends at the start of second trimester? Do we tell them earlier because there's two? When should I be gaining weight? I haven't gained any yet. Is that bad? Everyone says this so called "motherly instinct" thing will kick in. Where are you motherly instinct? Please come soon! I'm so clueless...