I started using ensime-emacs last month. What exactly is your problem?
If you are using sbt and emacs, I would recommend reading http://ensime.github.io/build_tools/sbt/ and http://ensime.github.io/editors/emacs/install/ first.
I basically followed the instructions on the sbt part and since I am familiar with emacs, I did not follow the emacs part and did it in my own way.
Although the documentation is not detailed, it helped me get started.