1. In the main menu.
2. You need to hang out with her and says the right things, so she is falling in love with you and if you go to bed, she will joining you. You can trigger the event, when you're going in the town in the evening. I won't happen at the first try.
3. If you downloaded the game from this official site here and updated (or downloaded the newest version) everything, you should get them. And if the event isn't triggert, you'll find her the most of the time in living room or on the farm. ^^