Hey There ~ I usually soak them overnight, but soak them at least 8 hours and you can change the water once it begins to get brown (it is soaking the tannins out of the almonds).
You can use varying amounts of water to get the consistency you like, I usually use 2-3 cups of water for every cup of almonds (but I don't really like it too thick), then I'll add one, 2, or all of the following: vanilla beans, molasses, dates or you could add someo ther type of sweetner ~ or none at all. Blend all this together and then strain it with cheese cloth (quite messy) or a nut milk bag (you can get one and purejoylivingfoods.com). Happy milk making!!!!!!!!