I've got about a million questions... I'm only about 0.1% through the books so my knowledge is pretty minimal.
Well I don't understand the whole warp thing at all ...
Where do I start....
What is a webway ? Can humans use them ?
It like a series of tunnels (that's the best word for it though it's more complex than that) that's sort of partly in the Warp and partly in real space, it allows safe travel across the galaxy much faster than travelling through real space but slower than true warp flight.
Yes humans can use it, anyone can really, and the Eldar didn't build it their creators the Old Ones did.
Is the Eldar warp different from the human warp ?
The Warp is simply that, there aren't different Warps- it's all one encompassing, chaotic realm.
If I looked out the window of my battle cruiser whilst travelling through the warp would it be all purple and swirly ?
If you looked out of a window whilst travelling through warp space you'd go utterly insane, the warp is everything and nothing- it's raw emotion and insanity, it's never the same for any person that looks at it (that's also why the 'windows' on ships passing through are shielded so those aboard can't look through them).
If I lived on a planet near a warpy bit of space would I have crazy dreams about demons ?!
Possibly, your planet would be home to a higher than average number of mutants, your dreams would be unsettled and pervading sense of unnaturalness would permeat the atmosphere.
Do smaller transport ships have warp... do you NEED to have a 'choir of psykers' to travel through the warp ?
You need a Warp Drive to traverse the Warp itself and a Navigator to use the Astronomicon (which is a choir of thousands of psykers directed by the God-Emperor who create a 'guiding light' of psychic power from Terra).
Most large ships have some sort of warp drive, basically only stuff that is small enough to dock within another vessel doesn't have a warp drive.
When the Chaos marines 'retreat to the warp' what do they do... are they in a dreamy state !? Or is it the same as the normal plains ?
They usually retreat to a daemon world, which is a world from real space trapped within the Warp- again the Warp/Immaterium differs depending on the individual viewing it but it's rarely a pleasant place even for Chaos Space Marines.
What about the Dark Elder ? is their Black Fortress in the warp ? Could it be attacked by Elder or Chaos ?
Their largest city, Commorragh, dwells within the darkness of the Webway where Slaanesh's influence is lessened on their souls- in theory anyone could invade it if they had access to the webway and could find it. Usually though the only non dark eldar other than slaves to travel their are the Harlequin Eldar.
Thanks in advance for the responses
No problem dude, I'm here to help