Spirit guides exist?
You can contact your spirit guides whenever you want to, they are constantly with you. All you need to do is simply talk to them. You can and should ask them to provide you with a sign, asking them to provide you one so you can feel more closely connected to them.
As far as I understand it you can't ask for anything specific like time and place, or the kind of sign. Simply trust that you will receive a sign that means something to you. If after a day or two you haven't noticed a sign ask again, you probably overlooked it or dismissed it.
For anything more specific I highly recommend a reading from Miss Beth's Angels. She's the one that taught me all of the above by the way. She can get in touch with your angels and spirit guides and learn their names and what they have to tell you at this time
You can Google her name to find her excellent website.