To install subversion (or SVN if you like keeping things short) is pretty simple to achieve in Ubuntu (as with just about everything else).

First, open up a terminal window and enter:

sudo apt-get install subversion

After entering in your password, the system will automatically grab the necessary packages that will need to be upgraded or downloaded and installed, and after a summary screen requesting your explicit go ahead, go about merrily on its business.

Once complete, you will now have the various svn command line calls available to you. (svn help is a great place to start!)

As for actually setting up the SVN, this post might help! :)