How do I successfully install apps on my Samsung Focus (Windows Phone 7)?

I get on Marketplace, browse through apps and select one like Facebook but when I tap install it ALWAYS tells me it cant get the information for it. My phone is about 6 months old and never been broken or anything. When it has the info and i tap buy it says to connect to my computer and now that I have, nothing. Fail. Can someone please tell me step by step the process of getting my computer to recognize my phone, get Zune, and actually install the apps?