First off, here's a link to the documentation for the Sling Pro. It has all the manuals and guides that came in the box:
If you need the SlingPlayer software, you can find it here:
If you forgot your admin password, here's how to reset your Slingbox:
As for how to hook your video sources up, there is more than one way to do it with the equipment you have.
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If you post back and say more about how you would like everything to work once it is set up, I can suggest how to hook the wires up. Specifically, what you would like to be able to watch and control from the Slingbox ? Also, do you need to be able to watch Slingbox while someone at home is watching a different show on the TV ?
Post back if you have more questions.
Hope this helps,