Adjusting to Hearing Aid Help?

I just got home with my first hearing aid, only in my right ear - Does anybody have helpful tips for adjusting to wearing it? I have a hissing sound going on that might drive me batty - and yes, I know I can go back and they will make adjustments to the unit. On the upside, it's so small nobody can see it - my 29 year old son thought it was hidden in my earring

I'm going to have to go in this afternoon - I've tried playing with the button to make my own adjustments and have succeeded in messing up the mask settings - now I have the constant ringing AND the hissing, not quite what I was going for.

I still can't tell if my left ear rings or not, there is no hearing loss in that ear - I just know there's lots of bells in my head