you click on it in items and then drag it to the guy
It will be after the train robbery.
you find it after you defeat the train game* at the bank entrance, so it is a good idea to go to rock ridge when on the train. *robbery shoot-potato thingy
First help the big headed boy in Dos Cactos to get a piece from a map. Then go to the bank after or before the robbery and near the bank accountant you will find the second piece of the map. After this leave town and check your map. A new location will be marked with a star.
go to rock ridge and get the map piece. then you go to the new star on your map.
how a map is interpreted (read), or meant to be 'read'
Get the saddle from the girl rancher at Rock Ridge and swap it for an oilcan at the Trading post in Dusty Gulch. Use it to fix the clock to get the train to arrive. Go on the train, and win the Train Robbery. When you go to Rock Ridge, you find that the gang has robbed the bank instead. Get the Map Piece from the roof of the bank.
You can board it in Diamond Plains when you first repair the Clock Tower. This triggers the Train Robbery sequence, without which you cannot get the second half of the map to the gang's secret hideout (top of the destroyed bank).
It is down a bit from Dos Cactos. You get two pieces of the hideout map. The first one is left on top of the burned bank in Rock Ridge. When you beat the Train Robbery, the gang robs the bank instead. While in Rock Ridge, go to the mine (upper right) and recover the Blue Tulip. Bring it to the big-headed kid in Dos Cactos and he will give you the other half of the map.
You use the legend to read the map.
Read the map's symbols correctly
The tulip will cure the big-head kid of his condition and he will give you the other half of the map (to the bandit gang's hideout). Combine this with the half found at the bank (after you foil the train robbery), and you can ride to capture the gang there.
Read it