1. Don't worry about this. No one starts with a complete grid. Focus on the basic grids of the first 6 primal bosses(Levi, Col, Tia, Yggy, Celes, Lumi). Depending on your starting team, just pick one and start with that or do a bit of research to see which team is the "strongest"(which element you have some of the better characters in) and focus on that grid. There are some weapons outside of the Primal bosses you should try to nab(like a Baha Sword or Dagger[these two are just the most highly suggest because of character race ratio.])
2. As a beginner, you basically start earning crystals through the Main Story Quest(MSQ), other means are through Story Events(which can net you about 300 just by completing the chapters), Battle Events(this will vary Crystal your earnings) and through trophies.

Tickets are your other means of rolling and again, these can be earned through events or once a week through daily log ins. You can also earn a ticket through the Co-Op section and buying it by completing daily quests.

Vane is a rather easy target to get since he isn't a limited character...yet. I would suggest you pick a better character and only start