How to put this part in

I bought my DW 3 years ago and I am just now installing it. :(I have dishwasher model PDW9880LOOSS. My question is the part no. 587 which is a nozzle…I’ve found it in the diagram but cannot figure how to put it on (it was at the bottom of the dishwasher and not installed…I put it where it looks like it goes but then the door would not close.
Here is a link to the diagram: http://c.searspartsdirect.com/lis_png/PLDM/G0511184-00002.png
Thanks,
Linda

Here is a link.
Check out Page 13 of the Use and Care Manual.
This part is only sued when you have removed the upper rack so you can wash large items etc.
http://genet.geappliances.com/search/search?site=gea-litlib_collection&ou=utf-8&tlen=150&client=gea-litlib_frontend&output=xml_no_dtd&proxystylesheet=gea-litlib_frontend&filter=0&getfields=*&q=PDW9880L&actualquerystring=PDW9880L00SS