I just got a hearing aid to demo…it uses a ‘high power’ dome over a RIC device connected to the aid.
I’m uncertain how to know how to put it in properly…suggestions, ideas, please??? 
Can be tricky, but basically you need to shove it into your ear canal until the wire is flush against the ear. If there is significant pressure or pain, stop. If the issues persist, return to your service-provider for another training session.