To build programs yourself in a Linux environment, you need to resolve dependancies first. The dependancies are those libraries and packages that the program you're installing depends on to be there. Everything we've done up to this point was to resolve all of those dependency issues so that we can do a nice clean install without running into any problems. Now that everything that will need to be resolved is, let's download the programs we're going to use.
[Sadly, I was working on this project pre-version 2.1, which you're welcome to try - but if you do, read the directions that come with it]
In Ubuntu, go to your home folder. If you click on the Places drop down at the top of the screen, you'll see a link to Home Folder.
Create a new folder titled: src [that's src in all lowercase] [right click - and click "Create Folder" to make a new folder]
Double click the downloaded Vrui-2.0-003.tar.gz [it should be in your downloads folder]
This will open up the archive in Archive Manager, you want to unpack what's in the archive into your src folder. So either go back to your folder screen in the background, and find and open your src folder and drag the Vrui-2.0-003 folder out of the archive into that folder. Or, click extract, when the dialog comes up asking were to extract to, locate your home folder (should be your log in name), and once there, double click on src. When Archive Manager has the src folder open, click extract. When it's done, quit.