Presuming bank 0...
Press PGM to enter program mode. Move to channel 001 by pressing 0 0 1 PGM (then "down-arrow" after entering each frequency below to move to the next).
Channel/frequency:
001 866.10000
002 866.88750
003 867.38750
004 867.91250
005 868.46250
006 866.71250
007 867.67500
On each of the above channels, press MODE until ED shows next to the channel number (e.g. top left of LCD will show "P001ED", "P002ED", etc.)
Press TRUNK. Press MODE until LCD displays "EDACS". At this point, you can also enter Talkgroup IDs, if desired (you'll have to update the firmware to version 1.02 first, to enter EDACS IDs in AFS format - see the RadioShack web site for new firmware).
Press PGM to leave the "trunking setup" mode.
To toggle between "Open" mode (in which it will receive all talkgroups on the system, except any you have entered and locked out) and "Closed" mode (in which it will only receive talkgroups you've programmed), press FUNC . (the decimal key).
Press SCAN. If the LCD shows "All channels locked out", press 0 to enable bank 0.