How do I know the state women are in?
Check the diary, either by choosing it in the inventory or pressing "Q". Hopefully you picked it up since the start, it's in your room.
Also, you're supposed to know about the State she is in because the choices you pick during their State Event tell you in which State she ended up and given your other comments, I'm sure you've not reached the State Event OR you just forgot you did them/what they ended up as.
The chair is the one in the fireplace, the one with a big circle on it, it's used to skip time far more quickly than sleeping in your room. Unless that specific chair is the one in your room (and that also has a circle to highlight it, even if to the side), I'd need the exact quote from the guide to know which one it mentioned.
The records don't serve any big purpose yet besides changing the tune that plays when interacting with the gramophone in the fireplace. In previous versions, the mom would be next to it but there was no scene yet, since that has gone nowhere as of 0.17.3, the Doc just removed her from there, so no scene with her yet in that area.
As a sidenote, even if this game is not your regular RPGM game (since there's no proper RPG elements like battles), these types of games rely on exploration and experimentation. You MUST have noticed the circles on some places that indicate interactivity with the objects/places you're in, so it's not uncommon to try them out at least once. Be more explorative, my dude