You should normally not have a problem making the IPA keyboard work. It uses "dead keys" to create the IPA characters. A “dead key” is a key that does not generate a character, but rather changes the character generated by a following keystroke. For example, in the IPA keyboard, to get the “ə”,you would type the dead key “=” followed by the “e” (=e).  Charts showing the how all the IPA characters are made this way can be found in [this PDF][1].

[![enter image description here][2]][2]


  [1]: http://scripts.sil.org/cms/scripts/render_download.php?format=file&media_id=IPAMSKLC1.4.pdf&filename=IPAMSKLC1.4.pdf
  [2]: https://i.sstatic.net/rITvu.png