Disconnect the Green wire (should be the color) that is going to the starter. Replace the fuse and push the start button.
Does fuse Blow.
If No,, the starter solenoid is shorted.
If yes,,, Remove starter relay from fuse panel, replace fuse and hit start button.
Does fuse Blow.
If yes,, check back with post.
If no, start relay is probably bad, but check with post first.