After copying the certificate to a file on your computer (I filed mine under Documents) then follow the next steps. Click the 3 parallel bars in the upper right corner of Google Chrome to open a drop down list.

Go to "Settings".
Scroll to the bottom.
Click the blue link for : Show Advanced Settings (last item on the page)

Under "HTTPS/SSL" there is a button called: Manage Certificates

A box will pop up with some choices at the top. Choose "Trusted Root Certification Authorities" Then at the bottom you will get a button to "Import". Navigate to where you stored the RMN Certificate and copy your location. Follow the prompts to complete the process and you are done. Sign in to RMN and you should not get a warning. No warning, means good certificate installation. Otherwise, try again.

Hope this helps. It was a maze for me, but eventually found my way.

Cheers, Capn Griff