If you use Windows, the best way is to use TortoiseSVN, but if you don't plan to download/update files from our SVN frequently, you can use a program like
http://downloadsvn.codeplex.com/

It's a simple stand-alone EXE utility which enables downloading Subversion (SVN) & GIT repositories. The utility is useful if you don't have SVN/GIT client, but you still want to download code from SVN & GIT repositories such as SourceForge, Google code or kernel.org.

Requirements: .NET Framework 2.0

The link that you submit for XOOPS SVN needs to look like this:

http://svn.code.sf.net/p/xoops/svn/xxx

where the xxx is the direct link to the folder you want to download. For example, to download the ZenTrack folder from the trunk, you would use:

http://svn.code.sf.net/p/xoops/svn/XoopsModules/zentrack/trunk/