I have written the following articles few weeks back. One thing I would like to add on to these articles is the patching order of Forefront UAG 2010.
You must have a base build Windows Server 2008 R2 SP1 with all Microsoft security and critical updates. you install the UAG from the this source Forefront_UAG_Server_2010_64Bit_English_w_SP1 with correct product key from Microsoft volume licensing center.
The following the order of patching UAG before you start configuring UAG.