CTRL + Z will kill the open-office automatically and give you your cursor
back.. Alternatively, space and type "&" without the quotes after your
command to open it in the background to have your terminal cursor
immediately come back to you.

To fix your error, use the command "ooffice -writer" to launch the word
processor with a new document... or add the file name of the document you
wish to edit after that command if it is in the directory your terminal is
currently at.