I believe Slackware comes with rpm, alternatively, use rpm2tgz.
Simply unzip the archive, change to the directory that has been created and run:
Code:
rpm2tgz *.rpm
installpkg *tgz
Or use the script that perfect_circle pointed you to. But yes, you need to install all the files for a working version of Open Office. You will probably find dependencies if you don't.
I hope this helps
--Ian