how do you....

Make an event triggered by your hero touching it, then go to the second page of events and find 'move event'. That should be what you are looking
for. As to another character, make n event where you want the other character appear, leave it blank, and use the event that you want your character to be on when he stops. Now use the move event and at the top select instead of 'Player', select the event where you want the other guy to appear. Press the button on the move event page 'Change Graphic'. Now select in which directions you want the other char to move, and if you want messages, it's the first button on the first page. Really you could just have one parallel proccess on the screen if the sequence happens as soon as you enter the map, but the way I described before is the most easy.

EDIT: heh, we posted at the same time!