'instal template' option not available in my Rush

Hi - I'm trying to add a 3rd party transition to Rush - I have watched numerous videos and have aleo spent quite a while with Adobe online help... I am aware that not all mogrts are compatable - THAT is not the problem - the problem is that when i go to the ••• option - the 'INSTALL ELEMENT' option is not there (as in all the videos) I repeatedly asked online if my version was not able to 'Install mogrts' but my questions were falling on stony ground. ANYONE? Thanks