I just try the cloudscape 3.5 today, is easy to get it working. I downloaded it many years ago from cloudscape.com.
My cloudscape 3.5 came as a java class file, about 10MB file, the class file itself is an installer
$ java cloudscape351
The install in /usr/local/cloudscape. I install everything is about 23M.
$ export CLOUDSCAPE_INSTALL=/usr/local/cloudscape
$ export CLASSPATH=$CLOUDSCAPE_INSTALL/lib/cloudscape.jar;
To test the class path is install properly:
$ java COM.cloudscape.tools.sysinfo
If you don't see the above information, means the class path was not setup properly.
Using the cloudscape client, cloudview
$ java COM.cloudscape.tools.cview
You can use the client to create table, store data, query SQL statement etc. You can try it yourself.