It’s as simple as finding one book to look through as a starting point.
The book is called “A Guide Book Of United States Coins” by R.S. Yeoman. This one is also lovingly called “The Red Book” by collectors and coin dealers alike, and is published every year. Inside the well written book it has both a value guide, and a breakdown on how to grade coins in it.
It also has every coin that the United States of America ever produced, from colonial coins to modern ones.
This could be a great place to get that potentially legendary collection started.