I've got quite confused about baby's sleep. My daughter is three months old and I've read in some places that she should be going to sleep in a dark quiet room, but I've also heard that they're not supposed to be on their own... so does that mean I go up with her for all her naps and at bedtime? We currently have her in the Moses basket downstairs for naps and until we go to bed. And this might sound silly but do I need to start waking her from her naps when a certain amount of time has passed?
Sorry to hear you have read so much conflicting advice. From a biological perspective you do not need to sleep your little one in a darkened room - if anything it will not help to support her biological and circadian rhythms and will impinge on night sleep! You can pop her in a separate room but don't make it pitch black.
And regarding her naps, I suggest you wake her after two hours max. Otherwise you might find if she sleeps too long during the day she will not be able to sleep at night - there is only so much sleep baby needs in a 24 hour period. In particular I suggest not letting her sleep too long in the afternoon before you put her to bed.