Now what? I don't know, which step of the installation instructions are you now at and are you sure you've completed the earlier steps to the letter
? The instructions are here: https://www.openoffice.org/download/com ... #linux-deb
I wouldn't muck about with the GUI as that leaves to much room for yourself to misinterpret what needs to be done. Just go to the folder where you extracted the downloaded archive, right-click the DEBS folder there and from the context menu select Actions > Open in Terminal Here. Then run the command for step 3. Next go to the desktop-integration folder and double-click the correct deb file there for your desktop to install it with GDebi. OpenOffice should now be in your menu.