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.
3. UAG-KB2288900-v4.0.1269.200-ENU
4. UAG-KB2585140-v4.0.1773.10100-ENU
5. UAG-KB2710791-v4.0.2095.10000-ENU
6. UAG-KB2744025-v4.0.3123.10000-ENU
UAG Articles:
Part 1: Install and Configure Forefront UAG Step by Step
Part 2: Publish RDS using Forefront UAG 2010 Step by Step
Part 3: Publish Exchange Server 2010 Using Forefront UAG 2010 Step by Step
Part 4: Redirect Web Application from HTTP to HTTPS using Forefront UAG 2010 Step by Step
Part 5: Publish SharePoint Server 2010 Using Forefront UAG 2010 Step by Step