It's a learning process like anything else in life
With some reading and advise from others on here along with a little effort on your part, you will succeed.
I am not ashamed to admit that I've been in this hobby for over 20 years and this is my first real round at Qt.
In the past we would battle sickness and disease in our tanks only to loose entire tanks and start over.
Keeping fish in observation was accepted as Qt, boy how things changed there huh.
I've been fortunate to learn the hard way with pest, disease and parasites on fish and corals through my years. I believe this trying and dark age time has given me experience and knowledge others cannot fathom.
I have been blessed with a great local forum and friend
@Humblefish who has always taken time to write excellent write ups and answer questions, I am not alone in regard to the fish Doc.
So after years of having playing with ick management and perfecting keeping fish fat and healthy, I still would wind up with that one "new" addition that would wipe my tank out.
This last system I built was my opportunity to go fallow for 76 days while my current fish of a few years could bask in the glory of medications.
All 7 fish are now completed copper treatment and about to undergo prazipro for internal parasites and gill flukes just to be safe.
I will never again add a fish without a full Qt first and to add to the health of my tank I decided to Qt all new corals and other inverts including clean up crews in a separate holding tank for 76 days
This can be seen as a pita or the smart and safe route to ensure maximum health and life span of your precious marine life.
Hang in there, time will afford experience and Qt will become habit
Good luck and happy reefing
BluewaterLa / mike