I use cwm in OpenBSD. There you have to install ibus and possibly a language specific input method (like pinyin input for Chinese). At first time, run the command ibus-setup and define the keyboard shortcut and the languages + input methods you want to use. After closing the setup tool it tells you three environment variables you have to set. Opening ibus-setup starts automatically the ibus daemon but this may be not persistent (at least not in OpenBSD) after reboot. So I put a line in line in .xinitrc:
After a new login you may hit the keyboard shortcut (by default: Super + space) to see if is running.
For adding languages you may start ibus-setup again in the terminal or you may assign a cwm keyboard shortcut for this. And make sure that you have the appropriate fonts installed if you are using languages with non-latin characters.