What version of Premiere Elements and on what computer operating system.
There is no Chroma Key, Green Screen Key, or Blue Screen Key in Premiere Elements Mac.
Are you working with Premiere Elements Mac?
I will give you full details of what to do once I have the version number and computer operating system
I may be away from the computer when you revisit your thread. So, I will post some information to help you sort through your issue.
If you have Premiere Elements 13/13.1, 12/12.1, or 11 Windows, you will find ChromaKay in the Expert workspace under fx Effects/Keying.
You will not find it in the Quick workspace of these programs.
If you have Premiere Elements Mac, there is no Chroma Key offered in those programs. The workaround is to look at the Expert workspace Difference Matte in fx Effect/Keying/Difference Matte.
Although Premiere Elements Mac does offer Videomerge which is not on my favorite list.
We will be watching for your results.