The wine cellar has the chemicals you need to mix in the laboratory. The key to the cellar is upstairs in the library type area, and you need the potion to burn that red web thing down the stairs. That one door you came to, I don't know where it leads.
Also, use more Tinderboxes and oil, you can't see shit otherwise. You get a lot more boxes. Oil is useful, but it's a bit rare, so use it but be conservative. You can afford to light more candles though, you get more boxes than oil. Also, watch out for monsters. And the self playing piano.
You're in Germany by the way if you were interested. Those stories were about Daniel being an archeologist. They lead him to like, a pyramid and he discovers these rare...orbs or something, but they don't seem to make sense. It's why he contacts Alexander in the first place I think. Try and listen more to the story parts and voice overs. It helps get you into the game and scare you more.
Monsters can't follow you through loading screens, just in case you ever need that.
That blue vision is your night vision to help you see, but you do need to light things every now and then.
That one note that talked about Agrippa, he's important later.
Listen to your sister more, she knows what she's talking about.