All you need to do is enter the last name as I instructed you above. Then repeat that find until you come to the right person. This action and the repeat of the find will only take a few minutes. You would at most have to repeat the find 25 times but unless the person was added last you should find then sooner.
AGAIN..... ONLY ENTER THE LAST NAME. NOTHING MORE, in the find menu option.
The GEDCOM code is not set up for you to locate by anything else.
Eventually you will find a line that looks something like:
1 NAME Ebenezer/Snell/
Shortly after that you MAY find the NOTE and OBJE lines for the person. If they are not there then this may be why the GEDCOM does not transfer them from ACOM to RootsMagic.
But, none the less, please copy the person information from the line just above the NAME line down to the next time you see a 0 (zero) in column 1.