As soon as you see grandma reading to the children, press Esc to get the options.

• Turn down the music. It is nice, but too loud.
  
• Turn subtitles off, they're ugly and the game has full audio.

Think of it mostly as an interactive movie. Some cutscenes get very long.

• You may need to talk to the right people in order to be allowed to do what you already know you need to do. (The interactive movie has dramatic reasons.)
  
• You can do almost everything with left-click, but right-click is examine/search, and you need that at least once.
  
• Remember these two points if you are stuck!
  
• The candle puzzle has an all-black cutscene, but the audio keeps going. Just wait.

• Save regularly.
  
• In fact, save right now, quit the game, and reload the saved game. (If you get an error, you may need to install the game to a folder with a shorter name.)
  
• Do not save during a dialogue, you may not be able to load that.

You can't die, but some people have reported the game crashed for them. I play on Windows 7 and have had no issues, so I think it's been fixed, but I don't know for certain.

If you want to read more, there's a small manual on Steam.