Downloading xwiki source distribution

Hello all, I am trying to download the xwiki source distribution, however, I haven't used SVN repository before and I am confused. I saw that under xwiki there are 3 subdirectories: branches, tags, and trunk. In branches I saw \bin\xwiki\branches\XWIKI_1_0, but in tags I found \bin\xwiki\tags\XWIKI_1_0_BETA_5. Which one should I important in my Eclipse? Also when I looked at the lib subdirectory I saw that a few jars are marked as 'UNKNOWN', e.g. alexa, etc Will the project run without them or where can I take those from? Thanks, Darina