You don't have to play through the desert again. Just use the included save file, that should start you right at Mahir. If you do want to for whatever reason though, the dynamite is for clearing the boulder blocking the path.
Again, a save is included in the new version. Check the "StarterSave" folder. As for the path it's hard to miss. Just keep trying to progress upward, you'll hit the boulders eventually.
